BORIS Johnson’s “smartest advisers” are telling him to agree to indyref2 quickly if Nicola Sturgeon wins a majority in next May’s Holyrood election, a senior Tory has claimed.

Peter Duncan, a former shadow secretary of state for Scotland, told the Sunday Times that if the UK Government continued to refuse a legally watertight referendum it would ultimately backfire on those who oppose independence.

The former MP said: “The way for Unionists to win the argument on independence is not to be seen to deny any clear mandate for a referendum that may exist after the elections next year.

“A ‘no, never’ approach will fan the flames for independence, as the smarter advisers in Downing Street are now making clear.”

It’s not entirely clear which advisers in Number 10 are making the case for indyref2.

Ahead of last December’s General Election, the Prime Minister’s main adviser, Dominic Cummings, warned Vote Leave supporters that if “Corbyn and Sturgeon walk into Downing Street on Friday 13, Corbyn will spend half next year negotiating some new deal he can’t explain then the second half of the year will be a cheated referendum in which millions of foreign citizens will be allowed to vote. It’s guaranteed chaos. And there’ll be another Scottish referendum. Politics will never be off the TV.”

Duncan told the paper: “The front-foot approach that I would recommend means that there needs to be a plan for an early response after next May’s election – dragging feet has never yet been proven to be a good platform for winning any argument.

“The route to defending the Union is to be prepared, then proactive and positive. Carping negativity looks likely to end in failure.”

Duncan said Brexit had fundamentally changed the argument on both sides. “For some, it may accentuate the argument for separation, but nationalists will have to argue that a Union with Brussels is more important to Scotland that a Union across the UK – that’s a tough argument to make, and a very difficult one to win.”

The Scottish Tories declined to comment on Duncan’s remarks.

Last December, after her party won 48 of Scotland’s 59 constituencies at the General Election, Sturgeon wrote to Johnson asking for the power to hold a legally watertight referendum to be devolved to Holyrood.

Number 10 quickly said no.

Recent polling has suggested a majority of Scots would now back a Yes vote.

Last week, a survey by YouGov said 53% would now back independence, up two points since January and the highest level of support for independence recorded by the firm.

That followed a slew of polls from Panelbase putting Yes ahead.

The poll also suggested the SNP were on course for a majority in the Scottish Parliament in elections next year.

There has, in the last month, been a rush of Tory ministers north of the Border.

Since Boris Johnson visited Moray at the end of July, Michael Gove, Alok Sharma, Rishi Sunak, Priti Patel, and Iain Stewart have all come to Scotland.

The SNP’s depute leader Keith Brown said: “The Tories still don’t get it. This is about democracy and not tactics.

“It is simply not credible or democratic for Westminster to try to dictate Scotland’s future.

“The opinion polls confirm majority support for independence is becoming the settled will of the people of Scotland and it is the Scottish people who Boris Johnson must listen to.

“That’s why the SNP will be campaigning for every vote in next year’s Holyrood election to make sure Scotland sends a message to Downing Street that cannot be ignored.”

Meanwhile, the leader of the Scottish Tory group in Holyrood has insisted she is “absolutely not” joining Boris Johnson’s cabinet when she heads down to the House of Lords next year.

However, Ruth Davidson didn’t rule out another “big job” in a few years time.

She told Times Radio: “You know, I’ve never wanted to live in London, my home is Scotland, my family is in Scotland, that is never going to change.”

Davidson said her leaving Holyrood “was never about the big job”.

“It’s leaving to take a step back at least until my young son and, hopefully, if myself and my partner are able to have any more children in the near future, until they get to school, and then I’ll make a decision about another big job. This isn’t it, I’ve been clear about that.”