LAST year, 50 million people all over the world switched their lights off for an hour in an international energy-saving campaign.

Tonight, organisers of Earth Hour hope one billion people will turn off their lights between 8.30pm and 9.30pm to support the fight against climate change.

For the past fortnight, activities have taken place all over Exeter to promote the Big Switch Off campaign, coordinated locally by Exeter City Council. The fortnight culminates today with a visit from green campaigner Brigit Strawbridge and her Big Green Bus.

Brigit, 49, from Worcestershire, co-presented the BBC2 series It's Not Easy Being Green and set up a charity, The Big Green Idea, 18 months ago to promote sustainable, eco-friendly living.

She will be joined by her former co-presenter Dick Strawbridge and representatives from South West Water and local environmental groups, including Low Carbon Exeter and Energy Saving Trust South West. There will also be a seed swap and plant exchange stall.

Brigit hopes the bus, which will be in Bedford Square between 10am and 4pm to promote the Big Switch Off, will be a big draw for shoppers. It will be staffed by eight volunteers, including Anne-Christine Favrod from Exeter, who will help show people how they can save energy and other ways they can live greener and more ethical lives.

Brigit said: "You don't need to wash your clothes on a cycle that's higher than 30 degrees. That saves 40 per cent of your electricity, which obviously saves your pocket.

"When you're boiling a kettle, only boil the water you need to use. The amount of energy a kettle uses is phenomenal."

With its eco-friendly flooring and walls, mini wind turbine and lights powered by solar photovoltaic panels, the bus will be a showcase for green living.

Organisers hope the weather is fine so visitors to the bus can make their own smoothies on a pedal-powered smoothie maker. There is also a library, an information technology section and a space upstairs where workshops and demonstrations will be held all day.

Brigit said: "The bus is beautiful. It is geared up to show individuals how they can make a difference instead of waiting for the Government to sort it out and saying, 'It's not my problem.'

"We have window boxes made out of English wicker and the sort of plants that attract bees. There are quirky things, there are fun things — there is something for everybody."

Volunteers on the bus will have a range of smart meters, which show people how much electricity they are using in their homes. Brigit said: "You save so much money because you just keep turning everything off. Anyone who saves energy will save money; it's just cut and dry.

"Quite often that's the starting point for people, especially with things being the way they are at the moment. Being green is not an expensive way of living. After the television programme, we had hundreds of emails and the majority of them were people saying, 'What you're doing is great, but it's all right for you because you have land and money.'

"Every time, I thought, 'No — you're so wrong.' The people I know who live the most sustainable lives tend to be people living on a shoestring."

Brigit believes some people ignore advice to live greener lives because they have been put off by the amount of information, statistics and figures about it.

She said: "We make it hands-on and accessible. We want to show people that being green is not just for hippies or for middle-class people — it is something everyone can do.

"The staff are very friendly and non-judgemental. It's important not to judge people just because they haven't started. Any little thing that people do to change makes a difference."

As well as the volunteers, visitors can talk to representatives from local environmental groups. Brigit said: "What we don't want to do is talk to people and have them go away and not know what to do next. If they want to do something after the event, they can connect with local groups."

Alongside the Big Green Bus, Exeter group Easy Green will put on a finger puppet show at noon, Dick Strawbridge will talk about renewable energy at 1pm and Low Carbon Exeter will give a talk at 2pm. Like all The Big Green Idea's activities, the event will be filmed.

Visitors can find out about anything from eco-friendly skincare products to organic baby wipes. Exeter City Council and the Big Green Bus are both giving away hundreds of energy- saving light bulbs and South West Water is providing water-saving devices to give away.

Brigit hopes shoppers will be inspired to switch their lights off tonight. "Every person counts," she said. "I think the Big Switch Off is important because it raises awareness and makes you think. If you could only see what energy you save in that hour.

"It's nice to be part of something huge as well. When I read that Earth Hour was trying to get a billion people to take part, it made me want to be one of those billion people.

"In a year, people can save £120 by not leaving appliances on standby. If everybody in the country switched to low-energy bulbs we could close down three power stations.

"If everybody joins in, it makes an enormous difference. We don't need to leave lights and appliances on if we're not using them.

"If everybody turned their lights off, you would be able to see the stars."

Brigit had some advice for people hoping to take part. "Life doesn't stop because you have got the lights off. Have a candle and have a family game, or go out and see if you can see the stars," she said.

"I would urge people to just this once switch the lights off for an hour just to see what it's like. You suddenly realise how many switches you have on standby and how many lights you have on in rooms you're not in.

"You increase your own awareness. Hopefully it will encourage people to switch off again and again."

Details: www.exeter.gov.uk/ bigswitchoff.