A Brexit "backroom agreement" between Theresa May and Jeremy Corbyn would "sell out the people of Scotland", Ian Blackford has claimed, as Labour refused to say that it would oppose the UK Government’s Withdrawal Agreement Bill.

The SNP leader at Westminster claimed Scotland's people and the will of the Scottish Parliament was "being ignored" over Brexit as he once again raised the issue in the Commons during Prime Minister's Questions.

Next week's European elections would give people in Scotland a chance to "make their voices heard whether Westminster likes it or not," declared Mr Blackford.

But, to Tory cheers, the Prime Minister responded by telling MPs: "The only party that wants to sell out the interests of Scotland are the SNP[in] their bid for independence."

She called on Mr Blackford and his party's MPs to back her Brexit deal when it is due to come back to the Commons for a fourth time next month.

Later, a spokesman for Jeremy Corbyn made clear that, as things stood, Labour would not back the Government’s Withdrawal and Agreement Bill[WAB] at Second Reading; the first Commons vote on the principle of the legislation.

However, he conspicuously failed to say Labour would oppose the bill; leaving open the possibility the Opposition could abstain at Second Reading and seek to amend the legislation in subsequent stages.

Mr Corbyn’s spokesman explained that after the Government announced it would bring WAB forward in the first week of June that there remained “gaps in our positions,” stressing how Labour needed UK ministers to make “further moves” before it could support Mrs May’s proposals.

“In relation to WAB, we’ve made clear there is no question of being able to support it without an agreement,” he said, pointing out how the legislation was “based on the same botched Brexit deal that has been rejected three times already”.

Asked if, therefore, Labour would oppose WAB, the spokesman said: “We can’t possibly support that[bill] in those circumstances.”

Asked repeatedly if the party would abstain, he replied: “Our whipping arrangements are always decided at the time. I’ve made very clear we will not support WAB without an agreement.”

The spokesman stressed how Labour had voted to trigger Article 50 and respected the 2016 referendum result but was trying to make the case for an alternative “sensible compromise” plan to leave the EU.

Asked if the cross-party talks could continue up to the publication of the bill, he emphasised how Labour had engaged constructively in them but they were “not an unlimited process”.

Chukka Umunna for Change UK seized on Mr Corbyn's spokesman's remarks, saying: “By refusing to rule out abstaining on the Second Reading of the WAB, the Labour Party is offering Theresa May and her Brexit plan a lifeline. This is the clearest indication yet that the Labour leadership is working with the Tory Government to deliver Brexit by any means necessary."

The London MP added: "The Brexit car is hurtling towards the cliff-edge and Jeremy Corbyn is not just stood out of the way but getting into the car and pressing down on the accelerator.”

After the Conservative and Labour leaders’ meeting on Tuesday night, Mrs May said the talks with Labour had been “constructive” but in them Mr Corbyn expressed concern about her ability to deliver on any agreement given what Cabinet ministers and leading Tory backbenchers had said in opposition to it.

During Commons exchanges, Mr Blackford asked the PM if a backroom agreement had been reached with Mr Corbyn “sell out the people of Scotland and force her shoddy deal through".

"The people of Scotland are none the wiser of what is going in these secret Tory-Labour talks. Scotland's people and the will of the Scottish Parliament is being ignored. Enough is enough,” declared the Highland MP.

“Why is the Prime Minister so afraid of giving the people of Scotland their say. The fact is at the European elections next week, the people of Scotland will make their voices heard whether Westminster likes it or not.”

Mrs May replied by insisting that the people of Scotland would know where things stood if the SNP backed her Brexit bill to enable the UK to the EU.

“If people want to vote for a party that not only is a Brexit party but also is a party in Government that can deliver Brexit, they should vote Conservative."

Later, Mr Blackford’s colleague Pete Wishart called on the PM to resign and let Scotland leave the UK too.

"The Government can barely double figures in the opinion polls; the UK now an international laughing stock with her backbench just wanting her gone, as does the nation.

"She is now going to bring back her Withdrawal Agreement for a fourth time as her backbench queue up to say they won't support her.

"Has the road not just now run out Prime Minister? For the sake of her nation will she please just go and let Scotland go too," declared the Perth MP

Mrs May replied: "It is in the interests of Scotland that it remains part of the United Kingdom and it is in the interest of the whole of the United Kingdom that we deliver on what people voted for in the referendum and deliver Brexit."