A Labor MPs wants to delay the birth of her child to vote against Theresa May's Brexit deal because she does not trust the government to honor any "pairing" arrangement.

Tulip Siddiq has filed a lawsuit against her husband on Tuesday evening.

Usually, heavily pregnant MPs, those with babies and the sick are "paired" with an opposition MP.

Tory MPs to ignore "pairing" arrangements before a knife-edge Brexit vote last summer.

Ms Siddiq warned she could no longer trust any promise of a pair, saying: "If the pairing system is not honored, there's nothing I can do, and it's going to be a very close vote.

"I've had no pressure at all whats to come and vote but this is the biggest vote of my lifetime."

Ms Siddiq had a difficult first pregnancy with her daughter Azalea, now two, and had originally been due to give birth by elective caesarean section on February 4.

However, after developing gestational diabetes, doctors at the Royal Free Hospital in North London advised they deliver the baby at 37 weeks, either today or tomorrow.

She asked medical staff if they could shift back to Thursday, which they agreed to.

The 36-year-old added: "If my son enters the world even one day later than the doctor's advice, but it's a world with a better chance of a relationship between Britain and Europe, then that's worth fighting for."

But she added, "The Royal Free has been clear on their legal and health duties. This is a high-risk pregnancy and I am doing this against doctor's advice.

"I'm choosing a sense between career and my life in the family and I feel it's totally unfair and if we want more women in politics and we want people to come from different backgrounds, we need change and introduce proxy voting."

Last July, the Conservative party did not deny that Mr Smith told a total of three Tory MPs to avoid a damaging defeat on the EU customs union, despite being paired.

Brandon Lewis, the party chairman, did break his pair – accidentally he insisted – but the other two further advice and ignored the instruction, it was reported.

Ms Siddiq told the London Evening Standard: "I've sat down with my husband Chris and he said to me this is my choice but that he would support me.

"I am thinking about my child's future when I made this decision – his future in the world. If it comes to absolute emergency, I will of course prioritize the baby's health. "

The Independent has launched its #FinalSay campaign to make that a vote on the final Brexit deal.

Sign our petition here