ALISON Thewliss has announced a bid to replace Ian Blackford as the SNP’s next Westminster leader.

In a shock announcement on Twitter on Saturday night, the MP said she felt she had a "duty to step up."

It means there will be no coronation for Stephen Flynn. The Aberdeen South MP had been expected to stand uncontested at the SNP Westminster group’s AGM on Tuesday.

He has yet to declare and while supporters believed he had the numbers to beat Mr Blackford it could be a much tighter contest against Ms Thewliss.

His chances may have been hampered by allies telling the Times that he was going to sack everyone on the SNP's front bench.

However, there are clear dividing lines between the two over the party's relationship with the leadership in Holyrood.

Ms Thewliss is closer to Nicola Sturgeon than Mr Flynn. Her Glasgow Central Westminster constituency and the First Minister’s Glasgow Southside Holyrood seat significantly overlap. 

Announcing her bid, Ms Thewliss wrote: “I've been working for independence for over half my life. Scotland is closer to achieving that now than ever before. 

“The Westminster group needs a leader who can build on Ian Blackford's achievements, and demonstrate that independence, far from being abstract, is the alternative to Brexit, the cost of living crisis and Tory austerity. 

“I had no intention of running for Westminster leader, but there is now a vacancy. 

“I believe I can do the job well, and I feel I have a duty to step up. 

“In my role as SNP Treasury spokesperson, I've challenged the Tories and their plans for austerity and fought for more support for people and businesses in this cost of living crisis

“I will also be a clear contrast to the two men shouting each other across the despatch box at PMQs on a Wednesday, illustrating the alternative vision on offer for Scotland. 

“I believe I have the experience and the attitude to lead the Westminster group forward so that ultimately, we can win the opportunity to leave the UK Parliament once and for all, and build a better future.”

In an interview with the Sunday Mail, Mr Blackford said he was ousted because of his support for the Scottish Government.

He said: “I saw ourselves as having that supporting role and I think there are some people in the group that would have preferred me to be a bit more independent. That has got more to do with it than ­anything else.” 

Asked if some ­fellow MPs thought he was taking instructions from Holyrood, he said: “I suppose so.”

He referred to the so-called Tuesday Club, whose members include David Linden, Gavin Newlands, Alan Brown, Stuart MacDonald and Mr Flynn, and said they had been unhappy since a vote on benefits in February.

“I think it’s fair to say what’s often referred to as The Tuesday Club, with one member in particular, there was a disagreement a number of months ago about a vote,” he said.

The SNP leadership in Edinburgh had urged MPs to abstain on a vote to raise benefits by just £10.07 a month and the state pension by £5.55 a week.

Mr Linden and Glasgow South West MP Chris Stephens defied the party’s orders and voted against the Government.

Mr Blackford told the paper: “First of all, let me be absolutely clear – I did not like what the UK Government were doing. But if you vote down the uprating of benefits, you can’t amend it. And so, on balance, I took the view that it was right for us to abstain.”

Kirsten Oswald, the SNP’s deputy Westminster leader, also announced she was quitting. She said in a statement it had been a “privilege to be part of the SNP leadership team” but it was time to “pass the baton to one of my many talented colleagues”.