LABOUR deputy leader Tom Watson said a pact with the SNP would be an “electoral dead end” and a “gift to the right”, as he delivered one of the most hardline speeches yet on the issue by a senior figure in the party.

Watson told the Scottish Labour conference in Perth, that the idea of a "progressive alliance" was a "road to nowhere", citing the 2015 general election campaign.

During that campaign, the SNP suggested it could help Ed Miliband's path to Downing Street by forming an informal coalition with Labour to lock the Tories out of power.

Miliband's refusal to rule out an alliance was exploited by the Tories.

Watson told delegates: "The Tories demonised the idea of a progressive alliance, of Labour propped up by the SNP - and used it as an electoral stick to beat us with.

"Telling the people of Scotland that they didn't need to vote Labour to get a Labour government, and telling the people of England that a vote for the Labour Party was a vote for the SNP.

"The mere suggestion of a progressive alliance is an absolute gift to the right."

He added: "The parties that supporters of the progressive alliance would hook us up with are actually no such thing.

"They might think we've forgotten, but the Lib Dems spent five years propping up a vicious Tory government.

"Enabling the bedroom tax, cuts to public services, tax cuts for millionaires while millions saw their living standards stagnate. That's not progressive.

"The Greens explicitly oppose creating the jobs and economic growth that working people depend on. In fact, under the mistaken belief it's the only way to save the environment, they argue for negative growth - otherwise known as a recession. That's not progressive.

"And here in Scotland you know better than anyone that nationalism isn't a progressive force.

"The SNP are a party that willingly continues to impose austerity on local councils in Scotland."

However, the SNP hit back and said Labour at Westminster had failed to oppose a Tory hard Brexit.

An SNP spokesperson said: “It is Tom Watson and Labour who are providing a ‘gift to the right’ with their shameful surrender to the Tories on a hard Brexit, which threatens to take Scotland and the rest of the UK off an economic cliff edge.

“If Labour spent half as much time taking the fight to the Tories as they did attacking the principled, progressive values of the SNP they might actually start to sound like an opposition rather than the pointless, shambolic, washed-up mess they have become.”