Science Secretary Michelle Donelan has returned from maternity leave to take up her Cabinet post again after three months away.

Chloe Smith has covered for her Conservative colleague at the Department for Science, Innovation and Technology (DSIT) since late April when Ms Donelan took a “short” break from frontline politics to have a baby.

The department was still in its infancy when she departed, having only been founded two months before by Prime Minister Rishi Sunak during a reorganisation of Whitehall.

Ms Donelan, a former culture secretary, tweeted on Thursday: “It’s great to be back after myself and my husband welcomed a baby boy.

“Huge thanks to Chloe Smith for her maternity cover.

“Looking forward to driving policy and DSIT’s work on some of the UK’s most important areas, developing tech to improve lives and creating jobs of the future.”

Ms Donelan, who served as education secretary for less than two days before resigning over former prime minister Boris Johnson’s leadership last year, became the second Cabinet minister to formally take maternity leave after announcing in December that she was expecting a baby.

The law had to be changed to allow current Home Secretary Suella Braverman to go on maternity leave in 2021, with Michael Ellis filing her role at the time of attorney general.

Before the law change, the covering minister would not have been able to have been paid if their colleague took paid maternity leave.

But the Maternity Allowances Act 2021 introduced formal paid leave.

Mr Sunak is widely expected to conduct a reshuffle of his Cabinet ministers, with suggestions that changes to his top team could come in September after the summer recess.

Ms Donelan’s stand-in Ms Smith has reportedly made clear to No 10 she is not looking for a new role in any reshuffle as she prepares to leave Westminster ahead of the next general election.

Ms Smith, who has dealt with a breast cancer diagnosis during her time as Norwich North MP, said the department had made “fantastic strides” during her tenure on its “mission to make the UK a science and tech superpower”.