Scotland's First Minister Nicola Sturgeon on Sunday softened her stance on the potential timing of a second independence referendum after Prime Minister Theresa May rejected her call to hold a vote before Britain leaves the European Union.

Sturgeon had called for a referendum to be held between autumn 2018 and spring 2019 but after May said "now is not the time," the Scottish leader said she could be prepared to hold a vote later as long as it was not too long after Brexit.

"It is for (May) then to say what timescale she thinks would be appropriate and then yes I am happy to have that discussion within reason," Sturgeon said during an interview with ITV.

Asked if a vote in 2021 would be reasonable, Sturgeon said it would not because too much time would have lapsed after Britain's EU exit, due in late March 2019, and there could have been too much divergence in areas such as regulations.

Scots rejected independence by 55-45 percent in a referendum in September 2014. But majority of Scots voted in favor of Britain staying in the EU in June.