LEADING ARTICLE : No more Paddy in the middle

You could easily imagine Paddy Ashdown as a square-jawed Outward Bound course instructor, giving them hell. "Get up that mountain, Blair," he would scream at Labour's newly recruited leader. "You horrible little man," he would boom as the hapless John Major fell into a stream. But although he was tough, Mr Ashdown would always be fair, never showing favouritism.

Until now. As the Tory ranks lie face down in the mud, exhausted and defeated, pigged out on port and cigars, Captain Ashdown has finally given up on the Conservative Party. They'll never be any good, he has concluded. The Liberal Democrats will refuse to keep the Tories in office if they lose their overall majority.

This is an extraordinary announcement, ending Mr Ashdown's longstanding policy of maintaining an equal distance between his party and its rivals. His despair with the Tories highlights the depth of their unpopularity and a widespread belief that nothing now can save them.

This historic shift also shows how much he thinks Labour has changed. For, although Mr Ashdown remains at arm's length from Mr Blair's party, he clearly sees it as one with which he can do business. Mr Ashdown has for some time felt more at ease with Labour than the Tories. But he has kept quiet, careful not to frighten Tories who might be worried that, in voting Lib Dem, they might be letting Labour in by the back door. With Mr Blair as leader, that concern has diminished. Indeed, any hint of associating with the Tories now seems, to Mr Ashdown, more of an electoral liability than an asset.

His new strategy carries risks. Tory HQ will lump Labour and the Liberal Democrats together, attacking one for the policies of the other. So if Labour politicians say: "No new taxes", Conservatives will point out that the Liberal Democrats would raise income tax by 1p to pay for improved education.

Mr Ashdown's calculation is that the policies which make his party most distinctive - constitutional reform, decentralisation, environmental improvement and a better education system - now stand a measurably better chance of being adopted by a Blair government than any credible alternative.

The weakness of Mr Ashdown's position is that he has made his move without securing anything in return from Mr Blair. Only time will tell whether this stance will work to the Lib Dems' advantage: it is still possible that in the event of a hung parliament he could deny office both to Mr Blair and Mr Major, threatening a second general election if Labour is not prepared to meet his terms for co-operation. He probably also calculates that in these circumstances, Mr Blair would not be personally averse to push in a more radical direction.

The core point is that New Labour needs the Liberal Democrats to help nurture its more radical instincts, which are likely to get duller the closer Mr Blair gets to controlling the centralised government machine, hardened by 16 years of single party domination. Mr Ashdown may now be willing Labour on to succeed, but he'll still need all his military hectoring, not to mention top class tactical instincts, to make sure that Mr Blair climbs all the way to the top of the netting.