Theresa May has quashed speculation that she would trigger article 50 on Tuesday and is now likely to wait until the final week of March to start Britain’s exit from the EU, the Guardian understands.

Whitehall figures had earlier said the prime minister was likely to move quickly this week if MPs and peers signed off as expected on legislation to allow the formal process of leaving the EU to begin.

Downing Street sources have repeatedly said May would take the action “by the end of March” but had failed to dismiss days of media reports that article 50 would be triggered this Tuesday.

That led to rumours in Westminster that a delay – perhaps until 27 March – was linked to the decision of Scotland’s first minister, Nicola Sturgeon, to push for a second independence referendum by the spring of 2019. One suggestion was that May did not want to appear cavalier about the future of the union by rushing to trigger article 50 a day after Sturgeon’s statement.

Sturgeon said a second independence referendum had become necessary because the UK government had failed to listen to Scottish concerns about what form Brexit would take. In particular, she was unhappy that there had been no compromise over the issue of single market membership.

“The UK government has not moved even an inch in pursuit of compromise and agreement. Our efforts at compromise have instead been met with a brick wall of intransigence,” Sturgeon said.

The prime minister retorted that she was planning to secure a deal that would work for the whole of the UK, accusing Sturgeon of “playing politics with the future of our country”.

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May said on Monday: “The tunnel vision that the SNP has shown today is deeply regrettable. It sets Scotland on a course for more uncertainty and division, creating huge uncertainty. And this is at a time when the evidence is that the Scottish people, the majority of the Scottish people, do not want a second independence referendum.

“So, instead of playing politics with the future of our country, the Scottish government should focus on delivering good government and public services for the people of Scotland. Politics is not a game.”

Scottish opinion polls show support for independence has strengthened since May’s hardline speech on Brexit in January and since her speech at the Scottish Tory conference earlier this month dismissing Sturgeon’s quest for a special Scottish deal with Europe.

The last three polls by BMG and Ipsos Mori have shown the yes vote has inched up from 45%, excluding don’t knows, to reach 48%-49% – effectively neck and neck with the anti-independence vote. That will strengthen Sturgeon’s belief she can convert more voters to support independence while the UK government presses on its plans for a complete departure from the EU.

Those in government who suggested May might trigger article 50 on Tuesday also said that if she missed that deadline the alternative would be the end of the month, to avoid clashing with Dutch elections and the anniversary of the Rome treaty.

However, they expected a quicker resolution given the likelihood that MPs will overturn Lords’ amendments to the Brexit bill, linked to guarantees for EU citizens and a meaningful vote on Brexit on Monday. The bill would then pass back to the Lords and could be given royal assent on Monday night.

A Downing Street source strongly denied there was any delay to the article 50 decision or that it was linked to Sturgeon’s intervention. Instead, they said May had always said she would trigger it by the end of March and that was why the final week of the month would be likely.

