THEY quit influential Labour roles to back the SNP. Now they’re urging others to follow them. Three high-profile Labour defectors last night urged that party’s voters to back the SNP and “lock the Tories out of Downing Street”.

The letter – from Tommy Sheppard, former assistant general secretary of Scottish Labour, Health Secretary Jeane Freeman, who was an advisor to then-first minister Jack McConnell, and Labour-to-SNP Glasgow councillor Anne McTaggart – was issued as Jeremy Corbyn completed a two-day campaign visit to Scotland.

Corbyn’s party is accused of “trying to face both ways on Brexit” and “shamefully” working with the Tories to “drag Scotland out of the EU against our will and to deny Scotland’s right to choose our own future”.

The letter states: “The SNP are the main challengers in every Tory held seat in Scotland – and only if enough people vote SNP on December 12 can we beat the Tories and lock them out of government.

“As former Labour supporters ourselves, we are urging Labour voters in Scotland to lend their vote to the SNP at this election so we can take the Tories head on and boot Boris Johnson out of government.”

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As well as his party role, Sheppard, who is seeking reelection in Edinburgh East, was a Labour councillor in England.

Freeman left McConnell’s Scottish Executive in 2005 and became Scottish Health Secretary last year.

And McTaggart, a former MSP, joined the ruling SNP group on Scotland’s largest council at the start of this month.

On Corbyn’s final day on the campaign trail in Scotland he was heckled by a pro-independence businessman and former SNP activist in Dundee yesterday over his position on indyref2.

Bus firm boss Bob Costello asked Corbyn what he planned to do about the “will of the Scottish people” over a second independence referendum as the Labour leader addressed a public meeting.

Nicola Sturgeon has said she’d make her party’s support for a minority Labour leadership at Westminster contingent on an agreement to grant a Section 30 order and clear legal hurdles for a referendum.

In the central belt on Wednesday, Corbyn ruled out taking that step in the entire first term of a Labour government – before changing that to the “formative years” of his premiership. By yesterday morning, that had shifted again to two years.

And last night the BBC reported that, speaking in Linlithgow, he told one woman he would not want another such vote. Corbyn has blamed any “confusion” over his position on reporters.

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Meanwhile, the SNP hope they can appeal to what remains of Labour’s once unbeatable voting bloc in Scotland. While the party once dominated at council, Holyrood and Westminster level, a recent YouGov poll suggests the gains made at 2017’s snap General Election will be reversed next month, making Ian Murray in Edinburgh South the country’s sole Labour MP once again.

That was the position in 2015 after an SNP wave turned almost all of Scotland yellow.

At this year’s European Parliament elections, Labour came fifth in what was their worst ever result.

But Corbyn has promised to plough investment into Scotland should he win – something he thinks could reduce demand for a second indyref. Yesterday, Sturgeon poked fun at his shifting scheduling, tweeting: “Yesterday it was ‘not in the first term’. Today, it’s ‘not in the first two years’. By the end of the week, at this rate, Corbyn will be demanding #indyref2020.”

The comments came ahead of an Edinburgh appearance that wrapped up his two-day Scots tour. Hundreds of supporters were expected at the capital’s McEwan Hall last night.

The evening got off to an auspicious start for Labour after a huge SNP logo, with the accompanying message of “Stop Brexit”, was projected on to the side of the building.

The text of the letter is as follows: “Dear Labour voters,

“This General Election is the most important in living memory.

“After years of Brexit crisis and Westminster austerity cuts, we have the chance to finally escape Brexit and put Scotland’s future in Scotland’s hands - not Boris Johnson’s.”

“Labour have spent the past two years trying to face both ways on Brexit. In recent elections and polling, support for the Labour Party has collapsed to fourth or fifth place in Scotland – and shamefully Labour MPs have been working with the Tories to drag Scotland out of the EU against our will and to deny Scotland’s right to choose our own future.

“This election is a crucial chance for people in Scotland to send a strong message to Boris Johnson and the Westminster parties - to stop Brexit, get rid of the Tories, and protect Scotland’s democratic right to choose our own future.

“A strong team of SNP MPs can deprive the Tories of a majority and secure the best deal for Scotland - holding Jeremy Corbyn’s feet to the fire on Brexit, demanding an end to austerity, securing investment for our communities, and putting Scotland’s future in Scotland’s hands.

“We need a strong voice for Scotland more than ever. We must come together in this election and make Scotland’s voice heard - and the best way to do that is to vote SNP.

“Don’t sit back and let Boris Johnson choose your future for you - on 12th December vote SNP to escape Brexit, lock the Tories out of power, and put Scotland’s future in Scotland’s hands.”