Alex Salmond has hailed a poll suggesting support for independence has increased substantially since Theresa May’s “hard Brexit” speech, saying: “Game on”.

But Labour said that the results showed that the SNP should rule out a second referendum.

The BMG poll for the Herald put support for independence at 49 per cent, with 51 per cent opposed, when 'don't knows' are excluded.

Read more: Support for independence surges following Theresa May's 'hard' Brexit vow

When the 10 per cent undecided are included, 43 per cent would vote Yes and 45 per cent No.

Last month a similar BMG/ Herald poll found 54.5 per cent to 45.5 per cent against independence, again when 'don't knows' are removed.

The latest survey also found most Scots do not want another vote before the UK leaves the European Union.

Just 38 per cent back a second referendum before then, with 48 per cent opposed and 13 per cent undecided, or 44 per cent for and 56 per cent against among those who have a view.

Read more: Support for independence surges following Theresa May's 'hard' Brexit vow

Since last month's poll, Theresa May has confirmed her plans to take the UK out of the single market in her Brexit speech.

Green MSP Ross Greer said that the most recent poll highlighted "the impact of Westminster’s refusal to seriously consider Scotland’s vote to stay in the EU or any compromise proposals which have been presented to them".

Former SNP leader Alex Salmond tweeted the poll, adding "Game on..."

Later on his LBC radio phone-in programme he predicted that there would have to be a "lead time" of roughly 16 to 18 months before any vote, adding: "I have always said I thought the autumn of next year was my favourite time".

In the Commons SNP MP Joanna Cherry told the Conservatives that the poll results showed that if Mrs May ignored Scotland's wishes over Brexit the chances of a Yes vote in a referendum were "looking pretty good".

But Scottish Labour's Westminster spokesman Ian Murray called on the SNP to rule out another independence referendum.

Read more: Support for independence surges following Theresa May's 'hard' Brexit vow

He said: "Rather than working constructively, the SNP is instead fixated on a second independence referendum. But as the latest opinion poll shows, people in Scotland are very clear that they don't want another referendum."

Meanwhile, it was reported that Theresa May’s team and the Scotland Office are “war gaming” with Scottish Conservative Ruth Davidson amid mounting speculation Nicola Sturgeon will announce her intention to hold another referendum at next month’s SNP conference.

No 10 said: “The question is not whether there could be a second independence referendum but whether there should be one – and the answer to that is a clear no.”

BMG Research interviewed 1,067 adults living in Scotland between January 26 and 31.