Labour�s Holyrood leadership yesterday slapped down Westminster MPs who want to hold a referendum on independence � an option that has been discussed at senior levels in the UK Government.

Labour's Holyrood leadership yesterday slapped down Westminster MPs who want to hold a referendum on independence - an option that has been discussed at senior levels in the UK Government.

There was a warning some MPs are going against their own Downing Street leadership, undermining the party in the Scottish Parliament, and that they need to learn the lesson from MSPs of being more disciplined.

Senior back-bench MPs have said it is time for Labour to reverse its opposition to such a vote, gambling that the SNP could be defeated and its cause would be set back by a generation.

Some in Labour at Holyrood fear the views have the tacit support of the Scotland Office in Whitehall - the part of the Westminster administration most enthusiastic about confronting the nationalist administration in Edinburgh.

However, a Scotland Office spokesman said the suggestion was "laughable" and that ministers "stand four-square behind the strategy" of Labour's Holyrood leader Wendy Alexander, who said it is "highly unlikely" Labour will agree to a referendum.

One Whitehall source commented yesterday: "It's an option people talk about, but not with any urgency. We can win a referendum at any time. The important thing is to make sure it fits in with our broader agenda, but at the moment, it's not under active consideration."

Such a reversal of policy could be achieved by Westminster approving a referendum, or by Labour MSPs shifting their position to force the SNP into a vote at Labour's time of choosing.

However, Ms Alexander is warning colleagues to stick to the line she agreed with the Westminster leadership. She is angered that the row risks a wedge being driven between the party's two parliamentary groups, offering an opportunity for nationalists to exploit.

A source close to Ms Alexander said she discussed the possibility of a referendum with Gordon Brown last May.

Her message is a warning to back-bench MPs Michael Connarty, David Hamilton and John Robertson, quoted yesterday calling for a referendum. Elaine Smith is the only back-bench MSP to break ranks by arguing for a U-turn, while former Labour minister Brian Wilson and leading MEP David Martin have also joined the calls.