Campbell 'optimistic' of seeing off rebellion on 50p top tax rate

The era of low-cost air travel will be at an end and hundreds of thousands of people will switch to smaller, less-polluting cars under Liberal Democrat tax plans, the party has insisted.

Sir Menzies Campbell moved to defend the green credentials of his radical tax proposals before a crucial conference vote today, insisting that millions of Britons must change their daily lives to prevent disastrous climate change.

He insisted that he was "optimistic but by no means complacent" about seeing off attempts to keep the party's commitment to a 50p top tax rate, despite claims that the rebellion led by the frontbencher Evan Harris was gaining momentum. Delegates at the Liberal Democrats' annual conference in Brighton will vote today on the party's tax plans, which aim to fund billions of pounds worth of tax cuts for low- and middle-income families through a shift to environmental charges and taxes on wealth.

In an interview with The Independent, Sir Menzies said people in Britain would have to change their behaviour to combat global warming. In some cases, this would be to their advantage - for example by switching off lights, TV standby buttons and so on at a time when energy bills were rising.

But he said the Liberal Democrats were ready to make "tough choices" on the measures needed, even if it made the party unpopular. "We are prepared to take that," he said.

Declaring that the era of £1 flights to European countries would have to be over, he said: "There is absolutely no point in having the ability to fly to places if, when you get the extremes of climate change, [they] are so great that you can't enjoy yourself."

Sir Menzies said a hike in the price of flights would not hit the poor hardest but those who could afford to pay more. He cited figures obtained by his party from the Government showing that only 36 per cent of people earning between £10,000 and £20,000 a year took air flights in the past year, compared with 80 per cent of top earners on £44,000 a year or more.

Senior figures also defended plans to impose dramatic increases in car tax, arguing that government-funded studies suggested that their proposed charges on new cars would encourage 72 per cent of people to buy a less polluting car.

Sir Menzies confirmed that the party was seeking a "notional target" of £15bn of savings to make its sums add up and preserve pledges such as free care for the elderly and the abolition of university top-up fees. Options include abolishing the Department of Trade and Industry and the national identity card scheme.

Yesterday Vince Cable, the party's Treasury spokesman, acknowledged that a defeat over the 50 per cent top rate of tax would be "damaging" for the party, but insisted that the front bench would abide by today's conference vote.

Privately, senior Liberal Democrats said the MPs backing the move to keep the 50p rate were "not mainstream figures" and said the front bench was backing Sir Menzies.

But Mr Harris insisted that he stood "a chance of winning" today's vote and claimed that even senior frontbenchers were sympathetic to his amendment. He said: "I think we will build up momentum behind it. That is inevitable. I think we have got a chance of winning."

He said that the party's tax commission had been split over whether to propose retaining the 50p top rate.

The rebel amendment will be proposed by Arnie Gibbons, a member of the commission, who insisted yesterday it was "wrong to say there was ever consensus on its rejection".