A Conservative MP has been accused of making a "scurrilous slur" after claiming a pregnant Labour politician had delayed giving birth to "make a point" about Brexit.

Labour's Tulip Siddiq defied doctors' advice and postponed her caesarean section by two days to vote down Theresa May's deal on Tuesday, when she was spotted being pushed through the voting lobbies in a wheelchair.

The Hampstead and Kilburn MP said she did not trust the government to honour pairing arrangements, after Tory chairman Brandon Lewis accidentally broke a pact with new mother Jo Swinson in knife-edge Brexit vote last year.

However Tory MP Kemi Badenoch accused Ms Siddiq of making a point to her pro-Remain constituents that was "irrespective of pairing", a system where an MP from a rival party also abstains so they cancel eachother out.

It comes after senior MPs have been campaigning for months to bring an end to "18th Century" rules by implementing a proxy voting system in the Commons.

Ms Badenoch told the BBC's Politics Live: "I have heard her [Ms Siddiq] speak on this issue privately before, and I think irrespective of pairing, I think she wants to make a point that she is doing this for her constituents.

"She represents a very strong Remain constituency and she wants to show that she did everything she could to stop Brexit. I think that is what this is about."

Her comments were condemned from Labour MPs, who described it as an "outright lie" and a "scurrilous slur" against Ms Siddiq.

Labour MP Stella Creasy tweeted: "Genuinely shocked Kemi Badenoch would choose to smear a colleague in this way - whatever the merits of Brexit or her desire to win the argument, impugning Tulip Siddiq on live tv with an outright lie is a new low even for this place."

Shadow home secretary Diane Abbott said: "Sad that Kemi Badenoch attacks fellow woman MP in this way, at a very vulnerable time for Tulip. Kemi can have no idea about the progress of Tulip’s pregnancy, so should not challenge Tulip’s good faith."

Shadow public health minister Sharon Hodgson added: "Exactly, the govt whips should pair her and count her through! That is the point she is making! How dare Kemi Badenoch make such a scurrilous slur!"

Ms Siddiq, who had a difficult first pregnancy with her daughter Azalea, now two, had been due to have an elective caesarean on Monday after developing gestational diabetes.

Doctors at the Royal Free Hospital in North London agreed she could shift the date back to Thursday to allow her to take part in the Commons vote.

She posted on Twitter: "My decision to delay my baby's birth is not one I take lightly.

"Let me be clear, I have no faith in the pairing system - in July the governmentt stole the vote of a new mother. It's my duty to represent Hampstead & Kilburn, and I will do just that."