Gordon Brown has ramped up pressure on David Cameron by suggesting he should agree to a debate on Scottish independence with Alex Salmond.
The former Prime Minister said it would be a good idea if Mr Cameron took on the SNP leader in the run-up to September’s referendum.
Mr Brown also repeated his warning that pro-union politicians were allowing nationalists to portray the vote as “England against Scotland”.
Speaking to journalists at a Westminster lunch, the MP dismissed arguments that Mr Cameron should stand back from the battle because he was toxic to Scottish voters.
“The Prime Minister has got to be part of this debate,” he said.
Asked whether he thought that meant Mr Cameron should agree to the Scottish First Minister’s demands for a debate, Mr Brown replied: “I think it would be a good idea if David Cameron did debate Alex Salmond, but I’m not involved in the negotiations.”
Firing salvos at both sides as he waded into the independence fight 100 days before Scots go to the polls, Mr Brown condemned Mr Salmond as “embarrassing”.
He said the First Minister had made making Scotland look “small” by unfurling a Saltire flag behind Mr Cameron when Andy Murray won Wimbledon.
But Mr Brown also criticised the way Scots had been warned that they would not be allowed to share the Pound if they vote Yes.
He complained about “patronising” government publicity material suggesting Scots would be able to buy fish and chips every day for 10 weeks with the money they save by voting ‘No’.
Mr Brown also made light of brickbats about his lack of attendance at Westminster since leaving Downing Street in 2010 by saying he will have to hire a tour guide.
But he declined to confirm that he will be staying as MP for Kirkcaldy and Cowdenbeath after the general election, saying only: “I am not going to make any announcements while we are fighting a referendum.”
In a swipe at Ukip leader Nigel Farage, Mr Brown joked: “Britain wouldn’t be Britain without Farage with a pint in one hand and a mystery lady in the other.”
SNP MSP Annabelle Ewing said: ““The pressure is now building on David Cameron to finally agree to the head-to-head debate the people of Scotland want to see – and he is fast running out of places to hide.”