The First Minister said the UK was facing “chaos” while “self-centred” Tory MPs were now busy contemplating replacing Theresa May as their leader.

“Today is a stark reminder that the UK is facing chaos and crisis entirely because of a vicious civil war within the Tory party,” the SNP leader said in a tweet. “What a self-centred bunch they are. They all need to go, not just the PM.”

She added in a separate post: “While Westminster crumbles further into chaos, with a UK government that has ceased to function, the Scottish Government will set out our budget for the year ahead - protecting public services, supporting the economy, and building a fairer country.”

Theresa May faces leadership challenge from Conservative MPs

Mrs May will need to secure the votes of 158 of her MPs this evening to stay on as Prime Minister, but will be severely weakened if over 100 vote for her to be ousted.

Labour said the prime minister’s weakness and failure had “completely immobilised the Government at this critical time for the country”.

Ian Lavery MP, chairman of the Labour Party, said: “The Prime Minister’s half-baked Brexit deal does not have the backing of her Cabinet, her party, Parliament or the country.

Nicola Sturgeon with Theresa May outside 10 Downing Street last month. The First Minister has criticised Tory MPs for forcing a leadership contest at a time of wider uncertainty caused by Brexit

“The Conservative party’s internal divisions are putting people’s jobs and living standards at risk.”

Arlene Foster, whose Democratic Ulster Unionist party has supported Mrs May’s Government, said: “I can’t say I’m surprised because being here in Westminster yesterday I did realise there were a lot of conversations going on, however my focus of course has to continue to be on the Withdrawal Agreement and the fact that the backstop needs to be taken out of that Withdrawal Agreement.”

Nicola Sturgeon criticises '˜self-centred' Tories over leadership contest