Nicola Sturgeon has been accused of placing a “lead weight” on Scotland’s economy after announcing her government will draw up plans for a second independence referendum that are ready for “immediate introduction”.

Unveiling her programme for government for the coming year, the First Minister announced a £500 million Scottish Growth Scheme to help companies cope with the fallout of the Brexit vote.

She said the three-year scheme represented “an exceptional response to an exceptional economic challenge” but then confirmed she will also consult on a draft Referendum Bill that can be tabled instantly if she concludes independence is Scotland’s best option.

But Ruth Davidson, the Scottish Tory leader, argued that the “biggest single economic lever” Ms Sturgeon could use to boost growth would be to rule out a rerun of the 2014 vote.

She told MSPs that the First Minister’s threat to stage another referendum was “stifling investment” in Scottish firms and posing a “direct threat” to economic growth. Even before June’s Brexit vote, Scotland’s growth figures were sluggish and last year it had a £15 billion deficit.

Ms Sturgeon made the announcement despite an opinion poll last week stating that only 37 per cent of Scots want another independence referendum before the UK leaves the EU, and a majority would vote No if one was held.