Nicola Sturgeon has been accused of trying to win Scottish independence by waiting for older Unionists to die off after she said “demographics” meant that delaying another referendum would increase her chances of victory.

The First Minister warned Boris Johnson that she had “time on my side” if he wanted to postpone a second separation vote by “playing a waiting game”.

She told the Financial Times: “You look at the demographics of the support for independence – well, I’m not sure that’s going to get you out of this conundrum.”

A series of polls have shown more than two-thirds of young Scots support independence, but pensioners overwhelmingly back remaining in the UK.

Ms Sturgeon’s official spokesman on Thursday refused to clarify whether she was referring to young independence supporters joining the electoral roll, older Unionists dying off, or both factors combined.

However, Angus Robertson, one of her closest allies and the Scottish Culture Secretary, faced a barrage of criticism last year for arguing that the deaths of elderly Scots were delivering a “gain for independence”.

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