Lynton Crosby urged PM to call SNP's bluff and approve indyref2 before Brexit

Theresa May is said to have been urged by her senior adviser to call Nicola Sturgeon's bluff over a second independence referendum and approve a new vote before Brexit is complete.

A leaked memo prepared by Sir Lynton Crosby apparently shows that he told the party to "harness the uncertainty caused by Brexit and use it to secure support for the status quo".

The revelation comes as Ms Sturgeon prepares to drop her preferred timetable for a new vote on breaking-up Britain in favour of a push for a soft Brexit. According to reports, she will tell MSPs this week that she will let her call for a vote before the spring of 2019 to slip, but keep the option of indyref2 on the table.

The First Minister announced in March that she wanted a vote on Scotland's place in the UK between the autumn of next year and early 2019 after Mrs May confirmed that the UK would be leaving the European single market.

According to The Times, Sir Lynton wrote a memo to senior figures in Conservative Campaign Headquarters the following day suggesting that the Prime Minister should agree to a referendum before the end of Brexit negotiations.

He said the SNP's demand for a fresh ballot was "out of line with soft voters' preference", adding: "While it may seem sensible to delay a referendum until after Brexit negotiations are complete this is not necessarily the best strategic position to adopt.

"Holding a referendum on independence before Brexit is complete will mean that voters have to grapple with the uncertainty of the outcome of Brexit in addition to the uncertainty of their choice in the referendum. Delaying the referendum until after Brexit is complete removes one of these unknowns."

He is also said to have warned in the memo that a Brexit result that was not supported by Scottish voters "could easily result in Scotland voting for independence".

However, Mrs May rejected the SNP's timetable for a vote just two days later, telling Ms Sturgeon that "now is not the time".

The First Minister promised to reflect on the referendum issue after a disastrous general election night which saw the SNP lose 21 seats, including those of Alex Salmond and the party's Westminster leader Angus Robertson.