BORIS Johnson has been warned that his plan to save the Union is sure to backfire.

The Prime Minister is preparing to travel north as he urges Cabinet colleagues to spend more time in Scotland in a bid to quell a surge in support for independence.

However, Ian Blackford said during PMQs that the move will only succeed in driving Scots towards a Yes vote.

The Tory leader was also pressed on his plans for a post-Brexit power grab, which he denied represents a “full-frontal attack on devolution”.

Blackford told the Commons: "Yesterday the Tory Party held a political cabinet with the Prime Minister in a panic about the majority in increasing support for Scottish independence. Apparently their great strategy amounts to more UK Cabinet ministers coming to Scotland.

"Can I tell the Prime Minister – the more Scotland sees of this UK Government, the more convinced they are the need for Scotland's independence. A far better plan for the Tories would be to listen to the will of the Scottish people."

The SNP Westminster leader asked: "So before his visit tomorrow, will the Prime Minister call a halt to his Government's full-frontal attack on devolution?"

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Boris Johnson responded: "I really don't know what [Blackford] is talking about.

"The only Bill I could think of that's before the House and will be coming before the House that I know enjoys cross-party support is the UK Internal Market Bill, although that is a massively devolutionary Bill which gives huge powers straight back from Brussels to Scotland, its principle purpose is to protect jobs and protect growth throughout the entire United Kingdom."

Blackford then pointed out that the promises made to Scots on the eve of the 2014 independence referendum have been broken.

He said: "In 2014, the people of Scotland were promised devolution-max, near federalism, the most powerful devolved parliament in the world. Instead, we got a Tory trade deal that threatens our NHS, an immigration Bill that will devastate our economy, a power grab that will dismantle devolution.

"Scotland's powers grabbed by Westminster, workers' rights attacked, the rape clause and the bedroom tax, our NHS up for sale. The overwhelming majority in Scotland's parliament, its MPs and its people, oppose all these measures."

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Johnson replied: "It's very clear that the UK Internal Market (Bill) is massively devolutionary ... 70 powers passed from Brussels to Scotland ... of course its purpose is very sensible which is to protect jobs and growth throughout the entire UK.

"Just on a political level, it seems bizarre to me that the Scottish nationalist [sic] party actually want to reverse that process."

The UK Government has promised that powers in at least 70 devolved areas will be transferred to Scotland after Brexit, with 111 powers in total going to Holyrood.

Constitution Secretary Michael Russell has dismissed these claims as “lies”.

He said the list of powers promised was in fact “a mish-mash of things the Scottish Parliament already has, things they’ve already decided we won’t have because of the frameworks, and things that could be automatically overridden by the decision of the UK to take a power away”.