The London mayor stated his opposition to devolving greater tax responsibilities to Scotland as a poll showed he had opened up a big lead over his rivals as the politician the public would like to see replace Tory Party leader David Cameron.
Nationalists last night seized on the intervention to warn that Mr Johnson’s comments offered a “grim insight” into Scotland’s future devolution prospects in the event of a No vote and a Johnson premiership.
Some 34 per cent of voters interviewed believe the London Mayor – who announced last week that he will seek to return as an MP at the general election – should be the next Tory leader.
The YouGov poll found he was 19 points ahead of Home Secretary Theresa May, while Chancellor George Osborne was third favourite with just 9 per cent.
However, in a departure from Mr Cameron’s stance on devolution Mr Johnson insisted there is “no reason” for pledging more powers to the Scottish Parliament over tax and spending in the event of a No vote.
Mr Cameron backed handing Holyrood the power to set its own rate of income tax and levels of some benefits as part of a package of enhanced devolution as set out in the party’s Strathclyde commission.
However, Mr Johnson, when asked about the plan, became one of the most senior Tories to set out his hostility to greater devolution for Scotland as he said greater powers should instead be handed to England’s major cities.
He said: “Alex Salmond has been thrashed in these debates, but for no reason we are promising the Scots more tax raising powers. There’s no need.
“What has England ever got out of this devolution process? If you want to have growth in the English cities then you should do what Manchester wants, what Liverpool, Leeds and all of us want – and that’s more tax raising powers.”
Pro-independence campaigners said there was now a serious prospect of Mr Johnson emerging as the UK prime minister after the 2015 General Election.
Blair Jenkins, Yes Scotland’s Chief Executive said: “With Boris Johnson being tipped for the Tory leadership, we’ve been given a sobering insight into the reality of what additional powers will be offered in the event of a No vote.