BORIS Johnson has been asked to predict whether he will lose his job before Scottish Tory leader Douglas Ross.

It came as the Prime Minister was mocked in the Commons after shelving plans to build a crossing between Scotland and Northern Ireland.

According to reports, Downing Street chiefs and Tory backbenchers are becoming increasingly disillusioned with their leader following sleaze scandals, spats over HS2 and a disastrous speech to the CBI.

At Prime Minister’s Questions, SNP MP John Nicolson highlighted reports which suggest proposals for a crossing between Portpatrick and Larne have been deemed "too technically challenging and expensive" by Downing Street.

The project, dubbed the “world’s most stupid tunnel” by Johnson’s former aide Dominic Cummings, had been championed by the Tory leader amid efforts to strengthen the Union.

Nicolson said: “Scots stood slack-jawed this week in astonishment at the news the Prime Minister has abandoned his ‘DUP bridge’ to Northern Ireland.

“Perhaps he’ll offer hot air balloons for the crossing instead, and inflate them himself.”

He continued: “Broken bridge promises to Scotland, broken rail promises to northern England. With buyers remorse consuming the Tory backbenches, who does he think will be defenestrated first? His hapless Tory leader in Scotland or himself?”

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Johnson side-stepped the question and instead attacked the Scottish Government’s record in government.

He pointed to the Union connectivity review, which is due to be published in the next week.

The Tory leader replied: “What we are delivering is the first thoroughgoing review of Union connectivity so that we look properly … at all those vital connections for the people of Scotland that have been neglected by the SNP, that this government is going to fix.”

Network Rail chairman Sir Peter Hendy has been tasked with drawing up the review, which is assessing transport links between England, Scotland, Wales and Northern Ireland.

Referencing the Scotland to Northern Ireland crossing, a UK Government source told The Telegraph: “Hendy has examined if this is affordable and practical and he concludes it would be technically very challenging at the moment."

Ross, who is an MP an MSP and a part-time football official, has been under fire recently after it was revealed he failed to declare earnings for 16 games he had refereed, as well as his MSP salary which he donates to charity.

The Scottish Tory leader has apologised for the "oversight".