LABOUR has challenged SNP MPs to back an energy price freeze in a Commons vote today.

Tom Greatrex, Labour's energy spokesman, said the Nationalists would be allying themselves with Prime Minister David Cameron and the big six energy companies if they refused to support the move.

Labour leader Ed Miliband has pledged to freeze energy prices for 20 months if his party wins the 2015 general election.

Alex Salmond refused to back the move when he was challenged at First Minister's Questions by Scots Labour leader Johann Lamont last week, arguing the energy companies would simply raise prices ahead of a price freeze.

But Mr Greatrex, MP for Rutherglen and Hamilton West, said: "If the SNP vote 'no' to the price freeze, they will be drawing a clear line between themselves and the Labour Party."

Mike Weir, the SNP's energy spokesman, said the SNP's plans would pave the way for "a more targeted and effective programme".