Brexit: Opposition talks deadlocked over interim PM if Boris Johnson ousted

Senior SNP figures warn other parties that talks 'have become little more than tea and biscuit meetings'

Opposition talks to oust Boris Johnson if he tries to force through a no-deal Brexit have been plunged into fresh turmoil amid splits over who should lead a temporary government.

Labour's John McDonnell rejected proposals for a "government of national unity", led by a senior MP such as ex-chancellor Ken Clarke, saying only Jeremy Corbyn could lead any temporary administration. Opposition parties are now "unlikely" to table a motion of no-confidence until after the EU summit on October 17-18, Mr McDonnell said.

It comes after Lib Dem leader Jo Swinson said opposition party whips would meet for the first time to plot different scenarios if Mr Johnson is toppled, including a government of national unity. The shadow chancellor told reporters in Westminster: "The rules are the rules. We are not into a government of national unity."

Mr McDonnell also revealed that Labour was seeking a meeting with Sir Mark Sedwill, the head of the civil service, to establish what would happen if the government was defeated but Mr Johnson still tried to "squat" in No 10 until after Brexit day.

Despite opposition to Mr Corbyn from the Liberal Democrats and exiled Tory rebels, Mr McDonnell said he was optimistic Ms Swinson could be persuaded to accept him as a temporary prime minister.

"I was brought up a Catholic. I'm a great believer in the powers of conversion," he said.

But a spokesman for Ms Swinson said: “Jo is a great believer in the power of mathematics.

"Jeremy Corbyn does not have the numbers and needs to make clear who he would support if we need an emergency government."

Tory MPs had been poised to rush back from their party conference in Manchester if a confidence vote was called – but failure to reach agreement on what comes next has stymied progress.

Senior SNP figures have expressed frustration at the deadlocked talks which “have become little more than tea and biscuit meetings”.

A party source said: "We went to the Supreme Court to bring parliament back – but Westminster has failed to take any meaningful action to get rid of Boris Johnson and stop an extreme Brexit. It's a talking shop.

"Time is running out – and sitting around doing nothing is not an option. The SNP has put forward a clear plan to secure an extension and election. It's time for opposition parties to unite around a plan and act – otherwise they risk sleepwalking into a Brexit disaster.”

Parliament has already passed a law compelling Mr Johnson to seek a delay to Brexit if he cannot secure a new agreement with the EU by 19 October.

But some MPs fear the prime minister could defy the law to force through a no deal – maintaining his do-or-die pledge to leave the EU on 31 October.

Several attempts to use parliamentary devices to obtain secret government Brexit papers have already been rebuffed by the Speaker.

However, MPs could make a fresh attempt on Wednesday to seek files on Operation Kingfisher about impacts on business; Operation Snow Bunting, relating to police responses; and Operation Black Swan, covering the worst-case scenario.