ALEX Salmond admits he has had a bruising campaign, literally, as he reaches for pain killers after suffering a cracked right rib while taking taking part in a charity football penalty-kicking competition

"It only hurts when I laugh" says Salmond who chuckles, while sitting in a car with SNP aides driving around the Gordon constituency he is battling to retain on June 8.

"It was spin football where you take a penalty after spinning 10 times and I scored, but then I fell down on the turf," says Salmond of the encounter in the Aberdeenshire town of Kintore.

The idea of flooring Salmond is something that would appeal to the Tory candidate hoping to oust him in Gordon and bring to an end his 30 years as an elected parliamentarian for the north east.

Clutching a wad of election literature and striding through the rural Aberdeenshire town of Huntly, Tory candidate Colin Clark is talking the talk of a heavyweight title-challenging pugilist, convinced he can defeat a veteran champion.

"He deserves a long retirement," Clark adds, in a sign of the growing confidence the Tories have that they could oust Salmond, who has defeated 10 previous Tory challengers.

Salmond was the MP for neighbouring Banff and Buchan from 1987 until stepping down 2010, as well serving as an MSP for the same area and later for the Gordon and Aberdeenshire East constituencies.

To listen to the Tories the seat, which takes in parts of rural Aberdeenshire and the commuter towns of Ellon and Inverurie, appears to be ripe for picking.

However, a third of the constituency is made up of the Granite city, including the Bridge of Don area and Dyce, home to Aberdeen International Airport.

"Every time I've fought a seat in north-east Scotland the Tories have said they are going to beat me," says Salmond who won Gordon with a 8,687 majority over the second placed Lib Dems in 2015.

"It's one short of a football team," he says of his Tory scalps, laughing again, but aggravating the right rib he cracked on the campaign opportunity with the Kintore pipe band.

In 2015 Clark finished a poor third and more than 20,000 votes behind Salmond. He insists he does not "underestimate the popularity of the SNP or Alex Salmond", adding that "it would be a massive blow if we unseated their biggest flag waver".

Or as he puts it, "All ships go up on a rising tide and go down on a falling tide."

So what is this unstoppable force that the Tories say will end the career of the politician who took Scotland from Labour a decade ago and won the Holyrood election in 2011, precipitating the referendum that almost ended the Union? When the Tories have not held the Westminster seat of Gordon since 1983 and which had a Lib Dem MP until Salmond's win in 2015?

But still Clark maintains that much of the area is natural territory for his party.

"Huntly is very blue," he says, as he makes his way through the picturesque town that the Tories are claiming as their own.

"The north east is a financially-strong part of Scotland," adding "it's the south east [of England] turned upside down".

Clark is a farmer and businessman who won the Inverurie ward on Aberdeenshire council, which he says show the Tories are on course to gain support.

But what's striking about Salmond's response is his reluctance to predict the outcome, although insisting voters remain "friendly" to him on the doorstep.

"The north east of Scotland is not natural Tory territory," Salmond says. "Even in Thatcher's pomp it wasn't Tory ground. People don't like having a hard-line, right-wing government."

"A reccurring theme on the doorstep is comparisons between Theresa May and Margaret Thatcher," adds Salmond and, implicitly, not in a fond way.

Salmond is speaking shortly after campaigning has resumed following the terror attacks in Manchester.

After attending a vigil for the victims at Newhills church in the Bridge of Don, Salmond heads off for low-level campaigning in the village of Insch.

But what of the Lib Dems, who held Gordon throughout most of the Thatcher era and beyond?

The party's candidate David Evans is canvassing in Ellon with former Lib Dem MP Malcolm Bruce, who retired in 2015 after 32 years.

"Malcolm Bruce is worth his weight in gold," says Evans as the 25-year-old candidate and the LibDem grandee take a breather from an afternoon's door knocking.

Evans is having none of it when it's suggested that Gordon is a straight fight between the SNP and Tories.

He responds: "My suspicion is that that just plays into Salmond's hands."

Evans, who has worked for LibDem MSP Mike Rumbles, says the crisis in the oil industry has hit the constituency hard.

He says: "Some people think we're well-to-do oilies, but that's not the case as there are real issues with high house prices and poverty."

Labour hopeful Kirsten Muat is focussing on the Aberdeen part of Gordon, where her party finished in fourth place on 3,441 votes in 2015.

The 20-year-old candidate speaks with a strong Mancunian accent despite leaving Stockport with her family for Inverurie at the age of 11.

"My main campaigning has been doing street stalls", she says as she speaks to voters in Dyce. "I've had a mixed response" admits Muat, who is back in the north east after finishing a politics a degree at Glasgow University.

She accepts Salmond retains a strong base of support, but claims talk of a second referendum has harmed his popularity.

She says: "From what I can gather he's a pretty good local MP. But a lot of people are not keen on him and he's seen as overbearing by some and a bit of a dinosaur who only talks about independence."