Alex Salmond has challenged Boris Johnson to a live debate on the EU Referendum.

The SNP's foreign affairs spokesman threw down the gauntlet this morning, challenging the Mayor of London to a debate live on LBC. Mr Salmond records a weekly radio phone in show for the radio station .

Mr Johnson text Prime Minister David Cameron before announcing he would campaign for the UK to leave the EU on Sunday.

Ukip leader Nigel Farage has already agreed to debate with Mr Salmond in the run-up to the EU referendum after the former First Minister challenged him during an interview on Sky News.

Mr Salmond told the programme: "I don't know if they've quite decided who they will be fielding yet. They seem to have spent a lot of time fighting with each other.

"That's the sort of folk they are. But yes, of course you debate all comers in a referendum campaign.

"If I may say so it has been Mr Cameron whose been tentative and sensitive about debating with people in recent history."

Downing Street signalled for the first time yesterday that a vote to leave the EU could trigger a second independence referendum.

First Minister Nicola Sturgeon has predicted that Brexit would “almost certainly” lead to calls for another independence referendum.

The EU Referendum will take place on June 23.