Scottish Labour has pledged to carry out checks on all of its constituency parties amid more concern about donations from trades unions.

The party has already admitted that the local party in First Minister Jack McConnell's constituency of Motherwell and Wishaw broke the law by failing to declare union donations.

Now the BBC's Newsnight Scotland programme has revealed that the problem may be more widespread.

It found that the Falkirk West party branch neglected to inform the Electoral Commission of two �375 contributions from Unison.

John Swinney: "Time for Labour to go"

The constituency is held by Labour MP Eric Joyce and independent MSP Dennis Canavan, who won the seat in 1999 despite his deselection by Labour.

Newsnight Scotland discovered that only 10 out of the 72 constituency Labour parties had declared donations of more than �1,000 a year, as required under Electoral Commission regulations introduced in February 2001.

Labour conceded that those rules had been broken in Motherwell and Wishaw where donations from the ISTC steel union were not declared.

The party said it was unable to state with confidence that similar undeclared donations have not been received elsewhere.

A spokesman said: "The responsibility for declaring donations and sponsorship lies with the local voluntary treasurers.

Thorough audit

"Despite the fact that we have regularly issued guidance, I cannot rule out the possibility that some local treasurers may not have fulfilled all their obligations."

Scottish National Party leader John Swinney said he had written to the Electoral Commission requesting a thorough audit of Labour accounts.

He said: "Every day brings now revelations about Labour Party sleaze and it is now apparent that it is not just in Motherwell and Wishaw where Labour has allegedly broken the law but in many of their constituencies in Scotland.

David McLetchie: "Labour ultimately responsible"

"Jack McConnell as leader of the Labour Party in Scotland is ultimately responsible for his party breaking the law and as first minister he has betrayed the trust put in him by the Scottish people and it has now become essential for the good of Scotland that Labour is removed from office in 2003."

The Scottish Tories accused Labour of breaking the very rules it had devised

Party leader David McLetchie said: "This whole sorry saga started with Labour and is now engulfing Labour.

"They designed the rules that they are now failing to live by, but those who break the rules must face up to the consequences.

"We need the full facts, full examination, full disclosure - because, as the first minister likes telling us, we should always be open and transparent about such matters. So far, they have failed."