“I didn’t always bring my bottles here, it’s only recently,” she said of her weekly visit to the recycling area. “I used to just put them in the bin. Then my conscience got the better of me.”

Now, in addition to enjoying the satisfying smash of glass when she lobs each bottle in, she had the pleasure of knowing she was fashionably green. “It feels good, doing your bit for the planet,” she said. “I’m going to start recycling newspapers, too.”

The conversion of Scots such as Robertson to the green agenda has not gone unnoticed by Scotland’s politicians. With next spring’s Holyrood election shaping up to be the most closely contested yet, all the parties are looking for issues that strike a chord with voters in the hope it will make a difference on polling day.

It seems every party has come to the same conclusion — the environment is set to be a political battleground. Green loyalty cards to reward greener living, green tax rebates, green power generation, a bottle tax, penalties for businesses with excess CO2 emissions — some novel thinking is going into winning the environmental vote.

This greening of Scottish politics is due less to the strategic cunning of the campaign managers than the need to keep pace with a very obvious social trend.

Last year the Co-operative Bank’s Ethical Consumerism Report said UK spending on green and ethical products increased at a rate of 15% a year to a new high of £25 billion. Fair-trade food purchases alone were up 60% in one year.

Only last week two of Britain’s biggest corporations showed the importance they put on demonstrating green credentials. Tesco sent a mailing to its 13m UK Clubcard holders. In future, customers will receive extra Clubcard points for re-using shopping bags.

Also last week, BP — a company facing environmental protests at its operations in Alaska — launched a scheme that allows drivers to make their car use “carbon neutral”.

The company calculates that an average year’s driving can be offset by a payment of £20 towards the cost of growing trees. Damage done by air travel and other activities can also be offset.

Mood watchers say corporations and politicians are right to be worried about keeping up with the green bandwagon. Wendy Martin is editor of New Consumer, a magazine devoted to ethical and environmental consumerism, which is produced in Edinburgh and has a UK readership of 33,000. She said the public is in danger of leaving politicians behind.

“People aren’t waiting for politicians to make changes,” she said. “They are not willing to just sit back and watch while each party makes its mind up on how green it can afford to be. People are taking matters into their own hands, in whatever small or large way they can. They are exercising their political will at the till.”

So what are the new policies Scottish politicians hope will wow the increasingly green electorate? Is the new approach a token gesture? And come May 1 next year, could it really mean the difference between power and opposition?

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