Contractors at the centre of a row holding up a £500 million city trams scheme today faced growing political pressure to "get back to work".

Contractors at the centre of a row holding up a £500 million city trams scheme today faced growing political pressure to "get back to work".

There remains no sign of work getting under way on the Princes Street leg of Edinburgh's trams project after a row broke out last week over "unacceptable conditions" imposed by the contractors, according to project leaders.

Talks resumed this morning aimed at reaching a resolution, but city MSPs hit out at the contractors consortium BSC - comprising Bilfinger Berger, Siemens and CAF - over the dispute.

"This trams saga is bearing all the hallmarks of the fiasco we had over the Scottish Parliament building," said former Tory leader David McLetchie.

"We cannot allow that to happen again.

"My message to the contractors is get back to work. You should never have downed tools."

Princes Street closed to traffic as planned on Saturday - when the work was due to begin.

The Edinburgh Pentlands MSP said any grievance should be resolved while the work takes place.

He added: "My message to the SNP/Lib Dem Council is get round the table and resolve this dispute and if the contractor won't go back to work, then get Princes Street open again."

Plans for the Princes Street phase of the £500 million trams project had been expected to close the main thoroughfare for a year.

A spokesman on behalf of the council-backed Transport Initiative in Edinburgh (TIE) said a process of dispute resolution had been taking place today.

But he added: "TIE is standing very firm in its demand and wants assurances from Bilfinger Berger that they will complete the work on budget and on time."

Nationalist backbench Lothians MSP Ian McKee said no more money should be paid and hit out at the disruption.

"Work had to start this month to ensure Princes Street was returned to its original state in time for the vital build up to Christmas," he said.

"Now business is being told no deal means more delay and more disruption."

But he branded the Tory criticism "shameless" after their part in pushing through the trams project, along with Labour and the Lib Dems at Holyrood, when the minority SNP Government wanted to ditch the scheme.

"The Tories can not wipe their support for Trams from their record - at the end of the day it is the votes of Tory MSPs that inflicted this chaos on Edinburgh and the city will not forget that," Dr McKee said.

News of the row emerged on Friday in a statement released by TIE, which said it had been given 48 hours notice by the consortium of "unacceptable conditions" it sought to impose before it would begin work in Princes Street.