A vote for Scottish independence from the United Kingdom could lead to the break-up of the coalition and a Conservative majority in Westminster before the next election, a former Cabinet minister has said.

Former Scottish secretary Lord Forsyth of Drumlean questioned whether MPs from Scotland would be thrown out of the Commons immediately after a potential vote for independence.

The Conservative peer's comments came at question time in the House of Lords following the publication this week of Scottish First Minister Alex Salmond's blueprint for independence.

Lord Forsyth asked the Advocate General for Scotland, Lord Wallace of Tankerness: "In the event that Scotland votes to secede from the United Kingdom in September of next year, will the general election still take place in Scotland in May of the following year and if so at what point will those Scottish MPs who are elected to the House of Commons be asked to leave?

"If it is before the general election, will it not result in the disintegration of the coalition and an overall majority for the Conservative party?"

Lord Wallace of Tankerness said there is no end to the "ingenuity" of Lord Forsyth.

"Those of us who have been elected to this Parliament in the Commons and received their writ of summons to the Commons I don't think have any clause in it that tells them to go," he said.

"In the unhappy event that Scotland chooses to leave the United Kingdom, there is no legislation in place that would stop the United Kingdom general election in 2015 applying throughout."

Tory Baroness Seccombe said the Commons would lose 59 Scottish members if there was a vote for independence.

"What would be the effect on this House? Would Scottish peers as foreign nationals be able to retain their seats? And would you be able to come here to answer questions?" she asked Lord Wallace.

Lord Wallace said Mr Salmond's White Paper states that the House of Lords is a matter for the rest of the United Kingdom to decide upon.

"We do not intend to have any contingency planning, but it is interesting to reflect that many of us are here as peers of the United Kingdom. I don't think we anticipate in Scotland a House of Lairds," he said.