Alistair Darling has urged the Labour Party to vote against a motion calling for renationalisation of the railways.

However the motion, from the TSSA transport union calling for a commitment to an "integrated, accountable and publicly owned railway", is still expected to be passed today in defiance of the party leadership.

The transport secretary tried to persuade delegates at the annual gathering in Brighton on Monday to tone down the pledge, holding out the prospect of ever greater government control of the privatised train network.

The Cabinet minister said it was "practically" and "philosophically" wrong to support renationalisation by stealth.

The TSSA wants to take train operating companies back into public ownership as their contracts come up for renewal, as happened with the Connex franchise.

But Darling insisted there is "nothing fundamentally wrong" with good firms running trains.

Earlier chancellor Gordon Brown had also said renationalisation would not be a priority for government spending.

"If the government had £22 billion to spend it will not be for an expensive renationalisation," he said.

"We will put investment in schools and hospitals first."

Vote

However observers expect the TSSA motion to be passed when the results of the vote is announced this morning, despite arm twisting from Darling and Tony Blair's teams.

The prime minister and party leader is struggling to assert his authority over activists, having already been defeated over a policy on local government powers and a motion on whether to debate the war in Iraq.

The small union, is being backed by big hitters including Unison, the T&G and GMB, which carry huge voting weights on the conference floor.

General secretary Gerry Docherty told ePolitix.com that the move would also be popular among voters, pointing to a YouGov survey showing 67 per cent of the electorate believe passenger rail services should be run in the public sector.

"We think it is important that every penny that goes into the railway is actually spent on the railway providing better services; it is clear that that isn't happening at the moment," he said.

"We think that having an integrated service is essential because it would streamline decision making. You need to have an integrated decision making structure because you need a very clear chain of command – one person has overall control of what is happening not only on the infrastructure side but also on the passenger services side.

"We have done some polling and only one in 10 people think that rail passenger services should be run by the private sector as they are now.

"There is clearly room for change and we think it is in the Labour Party's best interest to adopt this as a policy, to help them campaign for, and win a historic third term. We certainly want to see Labour win the election; we think this is a popular, vote winning policy."