The Ming dynasty has finally arrived. Political Editor GRAHAM DINES looks at the significance of the Liberal Democrat pledge to shift the tax burden on to polluters.

The Ming dynasty has finally arrived. Political Editor GRAHAM DINES looks at the significance of the Liberal Democrat pledge to shift the tax burden on to polluters.

IF Sir Ming Campbell had failed yesterday in his plans to ditch the Liberal Democrat commitment to a 50p top rate of income tax, former leader Charles Kennedy could have been allowed a wry smile.

Mr Kennedy was unceremoniously dumped by the party earlier this year, brutally shoved aside after admitting he was suffering from an alcohol addiction.

Instead of allowing him time to sort out the problem, the Lib Dems' “shadow cabinet” almost to a man and woman said they would no longer work with him. He had to go for the good of the party.

It left the activists in turmoil. Mr Kennedy was an iconic figure for them and they could not understand the manner of his passing.

It meant that whoever was elected to follow would at this week's annual party gathering in Brighton have to stamp his authority on the party with an eye catching policy, which would have appeal far beyond the confines of the conference hall.

Sir Ming Campbell has not failed his party. Despite some residual support among rank-and-file members for Mr Kennedy's general election pledge to slap a 50p tax rate on earnings above £150,000, he has turned his party's direction to the forefront of environmental activism.

Global warming is one of the key concerns of the electorate, especially those aged under 30. New Conservative leader David Cameron has recognised that - but the Liberal Democrats have come up with a headline catching policy whose substance is set to appeal to green voters.

Delegates in Brighton yesterday abandoned the 50p tax pledge and approved “save the planet” plans to hit gas guzzling cars with a £2,000 road tax and other environmentally friendly policies, including making airlines pay a pollution tax.

All this would raise £8bn to help pay for a 2p cut in the rate of income tax, a higher upper tax threshold of £50,000, and cutting corporation tax by 1% - benefiting 90% of taxpayers with only the top 10% of earners paying more.

Despite all the speculation before yesterday's conference debate that Sir Ming would have a fight on his hands to turn his party green, the new policy was given a comfortable majority by the conference.

Sir Ming said afterwards: “This was a very important day for the party because it was a day on which it had to choose between substance and symbolism, and it chose substance.”

Defeat would have been a devastating setback for the Campbell era, and could have lead left of centre activists demanding Charles Kennedy's return to the top job.

Instead, we now have a clear, identifiable policy for the Ming dynasty. He has carried his party with him as he faces up to do battle with a rejuvenated Tory Party under Mr Campbell and a post-Blair Labour Party.

Sir Ming has cleared a major conference hurdle, and he will have renewed confidence knowing that he has underpinned his authority.

His poor parliamentary performances and the Lib Dems' fall in the opinion polls had given rise to talk of a possible leadership challenge before the next General Election.

That's now evaporated, although it is difficult to see Sir Ming carrying on much beyond the next election. In 2010, he will be 69.

Yesterday's conference victory, apart from being a fillip for Campbell, has also lifted the stock of two Liberal Democrat younger front bench spokesman, who could be hankering after Sir Ming's job - Chris Huhne, the architect of the green revolution, and Ed Davey, the trade and industry spokesman..

The shift away from higher personal taxes to environmental taxation will also be a key bargaining chip for the Liberal Democrats if there is a hung parliament after the next general election.

Assuming the leader of the Labour Party is Gordon Brown, the man in charge of tax policy for most of the lifetime of a Labour government who has been roundly criticised for failing to introducing any meaningful measures to tackle climate change, could the Lib Dems work him?

Or is more likely they would make common cause with David Cameron's green Tories?

A hung parliament is far from certain. But if that is the outcome of the next election, Liberal Democrat delegates in Brighton may have unwittingly made a Con-Lib Dem coalition more likely than a partnership with Labour.

And who would have forecast that six months ago?