The proposal has annoyed some backbenchers who are angry that the maternity rights will be conferred only on secretaries of state and that they will be more extensive than those enjoyed by the public.

While Labour has backed the move, it is concerned that there is no provision for paternity leave nor other parental rights, apparently due to the urgency of having the measures implemented before Ms Braverman gives birth at the end of this month.

Under the previous regime, she would have had to resign if she wanted to take leave.

Whips have said they hope to pass the bill on Thursday.