ALEX Salmond is "seriously testing the water" about a return to Westminster, senior SNP sources have made clear while stressing he has still to make up his mind on what would be a dramatic return to his old political stomping ground.

During the past few weeks, speculation has been mounting that the outgoing First Minister and Nationalist leader, who has made clear he wants to remain in politics, has been looking to fight for a Commons seat.

Political opponents have claimed the 59-year-old politician has been taking soundings in the constituency of Gordon, which overlaps with his current Holyrood seat of Aberdeenshire East, as the potential target to fight the 2015 general election.

The seat is currently held by the veteran Liberal Democrat Sir Malcolm Bruce, who is standing down next May. In 2010, the LibDem deputy leader had a majority of 6748 with the SNP in second place.

The SNP has yet to choose any of its election candidates, which it is expected to do around the turn of the year.

During BBC Question Time on Thursday, Mr Salmond, asked about the possibility of standing for Westminster, said: "Absolutely decisively, I can tell you I haven't made up my mind. So you'll have to wait and see. But I tell you what, when I do make up my mind, you invite me back onto Question Time and I'll tell you why I did it."

An SNP colleague noted: "He's clearly set a hare running," while another said: "There's certainly a lot more substance to the speculation now. Alex loves Westminster; it's a big stage for him."

One senior Nationalist source close to the FM explained the attraction for Mr Salmond would be the prospect of leading a significantly increased group - the party currently has six MPs - "holding the UK Government's feet to the fire" on more powers and, potentially, "taking on Ukip and representing Scotland's interests" in a referendum on Britain's EU membership.

Plus, it has been suggested that his colleague Nicola Sturgeon, the incoming SNP leader and First Minister, would not want Mr Salmond "rattling around" on the Holyrood backbenches and presenting a permanent distraction.

"Alex wanted to get the idea out there, survey the scene and see what people think," observed one colleague.