St Pancras Station

I've always refused to own a car, and my work as an eco-auditor means I frequently travel by rail to my clients' homes and businesses around Britain.

My job involves helping people to cut the environmental impact of their domestic and working lives and reduce their carbon footprint, yet as I travel around, I can't help but notice the enormous amount of energy that's being wasted. Perhaps, if I spent a day pointing out the errors of our ways, I could make a small difference? I could even award points for the speed and efficacy of the response.

At St Pancras Station in London, the first stop in my day of eco-agitation, I approached the new platform being finished off by the builders beneath William Barlow's glorious 19th-century arched roof. Sunlight was pouring in – but every overhead bulb was switched on, too. All in all, I calculated well over one million watts of lighting being used unnecessarily.

I found the assistant station master and asked if she could turn off the lights where the sun was shining. She agreed that it was an awful waste, but said she said she wouldn't be able to turn them off, as there were so many companies involved, with six contractors on site. (She added that she always turned off all her own lights at home during the day.) Undeterred, I contacted the press office of London and Continental Railways and explained my quest. He said the lights were on to test them, in case they melted in the winter when they would be on for longer... When I explained that I had been in the station frequently over the previous three months and that all the lights had always been on in the day, he said he'd find the switch.

Several days later he came back to me with really good news. He said other passengers had also complained and that we had spurred the company into action. London and Continental has now agreed to install a mechanism in the lighting control box that will turn off the lights when the station is naturally lit – and he promised to have the system installed by the time the first Eurostar trains arrive in November. Over the course of a year, if the lights are turned off for an average of seven hours a day, it will save more than 1,250 tons of CO2. A very positive result.

Green Provocateur Rating: 9/10

McDonald's Restaurant

Fast-food restaurants create mountains of waste. So my second stop was the busy McDonald's at King's Cross. I wanted to have a veggie burger meal but to use a real china mug that I had brought with me for my cup of tea, instead of the throwaway cups provided. I thought I should let the floor manager know first, to avoid any problems. At first she saw no issue, but then returned and said her manager wanted to contact company headquarters before sanctioning the consumption of a hot beverage in a non-regulation receptacle. I stood aside and waited. She then came back to say that the management was awaiting health and safety clearance. As this was showing all the signs of becoming a bit of a saga, I cut my losses and crossed the road to another McDonald's.

This time I simply joined the queue and asked the counter assistant for my tea to be put into my china mug. He didn't even blink. So I sat down and enjoyed my veggie burger meal, washing it down with a lovely hot cup of tea from my china mug, to celebrate a positive result.

Later, I rang McDonalds' press office for the official line and was told that that the company had no real objection, so long as customers realised that it was their own responsibility not to burn themselves with their tea. (In a celebrated case, the company was sued in the US by a diner who scalded their thighs with coffee.)

If all of us who visit McDonald's were to switch to reusable plastic cups, we could prevent 90 million disposable cups from being dumped. Placed end-to-end, they would stretch for more than 8 million kilometres, or 200 times around the Earth. Fact.

Green Provocateur Rating: 10/10

Land Securities, Cardinal Place

The contemporary architectural fashion for putting large glass atriums at the entrances of new (or even existing) office blocks leads to widespread waste. Despite being designed with the express purpose of allowing in natural light, they frequently have their lighting on all day, every day. My third stop was the new Land Securities development at Cardinal Place in the City.

The building has two huge glass atria at its entrances, which were lit with numerous floodlights when I arrived. I explained my planet-saving quest to the receptionist and asked if she could turn off the lights. She replied not only that she was unable to do so, but that she didn't even know where the switch was.

She called the head of security and I asked if he could switch the lights off. He replied that he could not, as they had to be on 24 hours a day. He suggested I go and ask the Land Securities site office. I met a polite young lady there who said that if she was to turn the lights off in the atria, she would first have to ask all the tenants in the office block. I have to admit that I found the idea of a huge bureaucratic process having to be undertaken to request permission to turn the lights off in a sun-filled reception area somewhat amusing, but she said would contact HQ to get an answer for us.

Land Securities' head of environmental services, Dave Fairbrother, later e-mailed me to say the lights would be turned off on sunny days in future.

Turning off the two atrium floodlights for seven hours a day could save up to 32 tons of CO2 a year – more than five entire households would emit for all their gas and electricity use.

Green Provocateur Rating: 8/10

Zara

I ventured into the Zara clothing store. I was about to get a lesson in how complicated a company could make energy conservation. I had noticed as I walked by that the window display lights were on, despite being drenched with sunshine. I therefore asked the amiable manageress if she could turn them off. She said she fully understood the sense of what I was asking but there were no separate switches for the window displays. They had to be on all day, whenever the shop was open. All the switches were controlled from headquarters.

I rang Zara HQ, and was told that the light switches were centrally controlled to prevent store staff leaving the lights and air-conditioning on at night. When I suggested that the company could put light sensors into the window displays, the person I was speaking to agreed to go off and investigate. I was delighted when an hour later, the managing director of Zara UK, Mike Sherwood, came on the line and said my request had been explained to him. He thought it was a really good idea and felt it should be relatively easy to do. It would cut both the company's electricity costs and its emissions. Indeed, it was, as business people might put it, a " win/win".

If 10,000 shop windows across the UK turned off their displays for seven hours a day, it would save more than 39,000 tons of CO2 every year, equivalent to the emissions of a small town.

Green Provocateur Rating: 9/10

The Body Shop

In towns and cities across Britain, whether in winter or summer, there are thousands of shop doors left wide open, releasing all the precious heat or chilled air into the streets. The Body Shop is a chain that seems to have a particular penchant for doing this, which is surprising when you consider its image as an ethical retailer – the doors are open in all weathers, irrespective of whether the heating or air-conditioning gets wasted as a result. This was confirmed for me when I went into The Body Shop by Westminster City Hall.

Despite it being a nice warm day outside, the shop was kept cool by two whirring air-conditioners. The open doors meant that they had to work far harder, as they were in effect trying to keep the rest of Westminster cool as well.

I asked if staff could close the doors and thus keep the cool air in the store. The lovely manageress said she thought it was a brilliant idea, but she couldn't close the doors when the air-conditioning was on without permission from head office.

I got The Body Shop's press office number from its website, which boasts loudly about how it has been voted Britain's greenest company. The press office gave me the following statement: "The Body Shop is committed to being an environmentally responsible retailer and is currently reviewing store operational guidelines in line with changes in technology, which will allow us to become more energy efficient." So disappointingly, the doors will stay open wasting the air-conditioning in the meantime.

If one Body Shop store halved the hours that its air-conditioning was on for a period of six months, it could save 3,700kWh of electricity. This would be enough to light an energy-saving 11-watt bulb for 340,000 hours. Shame on you, Body Shop.

Green Provocateur Rating: 1/10

Sainsbury's

More than 17 billion plastic bags are handed out by supermarkets and shops in Britain every year, so I decided to try and see if I could help reduce this a little on my eco-tour. I popped into Sainsbury's, which felt very cold after coming in from outside. (They really need to do something about the open cooling display cabinets.) But this was not why I had popped in. Instead, my task was easy. It was merely to ask for a cardboard box to take away with me. The friendly assistant at the checkout was unable to help, but referred me to customer services, who said it was not a problem, although they did not have many as most had already been broken up for recycling.

When I contacted Sainsbury's head office for the official line, a spokesman said the company would always try and help provide customers with cardboard boxes if they preferred them to plastic bags, but that it had fewer available now than in the past as it is trying to replace them with reusable pallets. I left happy but I felt that I had picked a very easy one for such a big corporation. Next time, I must ask them to put doors on their in-store refrigeration systems.

Of course the easiest way for Sainsbury's to slash the hundreds of millions of plastic bags it hands out free every year would be to charge its customers 5p per bag, just like Ikea has done, slashing the number of bags wasted by a fantastic 95 per cent.

The Scottish Executive recently calculated that the oil used to manufacture eight plastic carrier bags would power an average car for a kilometre. Therefore, if we all either brought our own reusable bags or reused cardboard boxes for our groceries, we could save enough oil to drive 2,125,000,000 kilometres by road.

Green Provocateur Rating: 9/10

Boots

One of the reasons our planet is being needlessly destroyed is because we have become a throwaway society. Things that were once made to be used over and over again have been replaced by disposable items. Kitchen towels, floor-wipes and razors are now all disposable. Even the humble handkerchief is in danger of extinction due to the ubiquitous paper tissue.

To tackle this in a small way I went into Boots, where my eco-challenge was to ask if the company would stock real cloth handkerchiefs so people could choose them instead of the disposable alternative. I noted as I went in that the automatic doors kept the air-conditioning in, earning Boots good Green Provocateur points. The assistant looked blank when I asked him for real handkerchiefs and laughed when he admitted that it took him a moment to realise what I was talking about. He said the store didn't have any, but that such decisions were taken by head office, of course.

A spokesman for Boots' PR department said it was a complicated question I was asking. This had me chuckling but he promised to get an answer for me. When I suggested the company stock them and place them beside the paper tissues as a eco-option, he agreed to ask Boots' buyers to have another look at the idea, but he was not optimistic. It's a shame. If 20 million Britons switched to cloth handkerchiefs, it would save a whopping 14,080,000,000 tissues every year.

Green Provocateur Rating: 3/10

Tesco

Co-op supermarkets has announced it will cease selling environmentally damaging traditional filament lightbulbs this autumn. This inspired me to ask Tesco if it would do the same, as tungsten bulbs use 500 per cent more energy than new-generation bulbs.

The cheerful manager said his store had been doing a very good trade in energy-saving bulbs but he could not phase out the wasteful bulbs without permission from head office. He added that he thought what I was trying to do was a very good idea. I noticed on my way out that at least the naturally lit window areas had their lights turned off. When I contacted Tesco's PR department the next day, the woman I spoke to promised to get back to me. She kindly did so that afternoon, with the unhelpful news that while Tesco had been really pleased with the rise in sale of energy-saving bulbs, it had no plans to stop selling the wasteful old bulbs.

This was disappointing as I could not help but think how exciting it would be if Tesco saw the light on this one issue, considering the company's massive market share. If Tesco refused to sell 10 million tungsten bulbs, it could save more than 400,000 tons of CO2 a year for the next 10 years, as the bulbs last up to a decade. This would potentially lead to a massive saving of 4 million tonnes of carbon. This is the equivalent of all emissions over a year from 666,000 British homes. What a pity.

Green Provocateur Rating: 0/10

Palestra Building

If you happen to be in any of the UK's commercial or financial districts at night, you will be faced with walls of fully-lit, but empty, office windows. The Palestra building in Blackfriars Road has long irritated me as I cycle past it at night, and quite often the first two floors are the most brightly lit on the entire street. There is a huge conference room on the ground floor that has more than 120 lights, and every time I've passed they've been on while the office is completely empty. I went to look around the side of the building and found an empty loading bay externally floodlit and with all the internal lights on. It had a large sign up saying it was not in use.

The head of security came out to see what I was up to. I explained I was not trying to break in, but wanted to know if he could turn off the lights in the empty conference room and the loading bay. He said what I was doing made sense and thought that all the recent flooding was linked to global warming. He proceeded to the back of the building, while I went outside to savour the drama as the lights went out. He successfully turned the loading bay and conference room lights out, while I cheered him on.

The building is leased by Transport for London and I contacted its press office the next day. There, a spokesman nearly ruined the good news story by saying the loading bay and conference room lights could not be turned off as they were centrally controlled and that the loading bay was in use 24 hours a day. But this did not detract from the excellent response from the security officer. If the LDA placed movement-sensitive lights on the loading bay, it could potentially save 36,000kWh a year. This could boil enough water for up to 720,000 cups of tea.

Green Provocateur Rating: 8/10

Southwark Tube Station

I have long wondered why Britain does not follow the example of Germany and install escalators that only run when they're needed. I decided to put this on my eco-intervention itinerary and to tackle London Underground about it. I went to Southwark Tube station to see if it had escalators running that were not being used, due to the low volumes of passengers using this station late at night. The station won good points as staff only had the minimum number of escalators turned on, but those that were running were empty. In Germany, metal plates are fitted at the top and bottom that activate the machinery when you step on, and deactivate it when you step off.

When I rang London Underground the next day, a spokesman said its stations had different commuter patterns to German metro systems. I couldn't help chuckling, as it sounded like another "wrong type of leaves" excuse. When I asked if the network would consider installing these " people sensors" on appropriate escalators, he said engineers were re-evaluating them at present, but did not think it would be appropriate. But over the course of a year, 50 such escalators could save up to about 800,000kWh. This would provide all the electricity needs for 153 families, without even installing a single solar electric panel.

Green Provocateur Rating: 3/10