PROFESSOR Sir John Curtice has issued a warning to the First Minister after a new poll suggested support for Scottish independence stands at 45 per cent in favour and 55 per cent against when “don’t knows” are removed.

YouGov’s poll for The Times, coming as Nicola Sturgeon becomes Scotland's longest-serving First Minister, found the same headline result as the 2014 Scottish independence referendum.

YouGov polled 1115 Scottish adults between May 18 and May 23.

Sturgeon’s approval rating was a net positive, with 51% saying she was doing well and 42% saying she was doing badly.

The percentage of people backing Yes was at 38%, support for remaining in the Union at 46% and “don’t knows” on 11%.

READ MORE: Sunday National: Nicola Sturgeon fires indyref2 starting gun in exclusive essay

The poll also found 59% are opposed to having a referendum before the end of 2023 while 28% were in favour.

The SNP plan to have another vote on the constitutional question by the end of next year.

However, 42% of people were in favour of having another referendum within the next five years, with 41% opposed.

Elections expert Curtice warned that the First Minister would soon need to try and win over more Scots to her constitutional vision.

He told The Times: “Caution was arguably a key feature of Ms Sturgeon’s handling of the pandemic.

“But at the same time, undue caution is an accusation that has been levelled against her by the more impatient supporters of independence.

“But if her handling of the pandemic is not to prove the one and only achievement for which her time as First Minister is remembered after she vacates Bute House, she will soon need to strike out and try and persuade her fellow Scots of the merits of the vision that brought her into politics – a vision for which there is seemingly still not majority support.”

READ MORE: Nicola Sturgeon: Now is the time to debate Scottish independence

Meanwhile, Scots were also polled on their Westminster voting intention. The SNP were on 46%, Labour on 22%, the Conservatives on 19%, the LibDems on 6% and the Greens on 3%.

Among Holyrood’s other parties, Anas Sarwar had a net positive approval rating with 35% saying he was doing well and 30% badly.

For Douglas Ross, 18% said he was doing well and 55% said he was doing badly.

Analysis of the Westminster results by Professor Curtice said they would translate into 53 seats for the SNP, three for the Scottish Conservatives, two for the LibDems and one for Scottish Labour.