At the age of 25, Labour's Keir Mather becomes the youngest person in the House of Commons.

But within hours of his victory, he faced criticism over his age, with veterans minister Johnny Mercer comparing his generation of politicians to The Inbetweeners.

The Conservative MP said that while it is "always good to get new people into politics…you've got to have people who have actually done stuff".

"This guy has been at Oxford University more than he's been in a job," he told Sky News.

Average age of MPs is 51

But despite Mr Mercer's concerns, MPs are not getting younger.

At the last general election in 2019, the average age of an MP was 51.

The lowest it has been in recent years was after New Labour's landslide victory in 1997 - when the figure stood at 49.3.

But it has remained around 50 since the late 1970s.

Since then the House of Commons has been dominated by the middle-aged.

At the last election, more than half of MPs (57.8%) were aged between 40 and 59, with almost a third (30%) in the higher 50 to 59 bracket.

Out of the 16 by-elections we've had since then, all but one resulted in someone younger being elected.

The exception to this was Samantha Dixon, 57, who held City of Chester for Labour after Christian Matheson, 55, resigned over sexual misconduct allegations.

New MPs, whether voted in at general elections or by-elections, are usually younger than their predecessors, however.

Young MPs quitting

While the title of Baby of the House doesn't carry any of the rights or responsibilities of Mothers and Fathers of the House, it does come with challenges.

Young MPs are still a minority. Currently, just 3.5% of them are under-30.

The SNP's Mhari Black made history when she became the youngest MP to be elected since 1832 at the age of 20 in 2015.

But earlier this month she announced she will be stepping down at the next election, telling the News Agents podcast that she was "tired" of the "toxic environment" at Westminster.

Ms Black, now 28, described it as "one of the most unhealthy workplaces" where "unsociable hours" mean it "feels like you are spending a lot of your life there" and you can "never really switch off".

Dehenna Davison, elected Tory MP for Bishop Auckland at 26 in 2019, is also already stepping down.

She told Sky News she has faced a "deluge of derogatory comments" as a younger MP but said the Commons needs "people from all walks of life".

Former Baby of the House Nadia Whittome took several months away from her job as Labour MP for Nottingham East as a result of post-traumatic stress disorder.

While the cause of her ill health was unrelated to her job, she said it was "not feasible" to manage it alongside her parliamentary duties.

She told Sky News the lack of younger MPs "isn't surprising".

"Considering all the challenges we're on the sharp end of, whether that be insecure housing, work, or tens of thousands in student debt, I think those are all obstacles to political participation," she said.

Lack of experience - regardless of age

Figures also show that although most MPs are over 40 - the majority are still relatively inexperienced - regardless of their age.

In 2019 the majority of MPs elected had fewer than five years of parliamentary experience - with only 11% in parliament before 2001.

Ms Whittome added: "I think it's a good thing we have people from diverse backgrounds in parliament - and that's not just people who already have parliamentary experience, that's teaching assistants, nurses and teachers.

"I always get asked whether someone in their 20s has had enough life experience to be an MP and the answer I always give is my generation has a lot of life experience that most MPs don't have.

"We grew up on austerity and spent years in precarious flat shares with no hope of owning our own homes.

"I've never doubted myself or my ability to be able to represent my constituents because of my age."

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Asked what advice she has for the new Baby of the House, she said: "I'm really excited not to be the only Gen Z MP.

"I'd say the most important thing is to stay confident and remember why you went into politics in the first place.

"I found developing relationships with colleagues who have been in parliament longer helpful too - as you don't get much guidance on how to set up your office or run your team."

During his campaign, Mr Mather said his age means he can relate to younger voters struggling with the cost of living and housing crises.

Speaking to Sky News, his mother Jill Tambarros referenced his experience as a senior public affairs adviser at the Confederation of British Industry (CBI) and as a parliamentary researcher for shadow health secretary Wes Streeting.

"He doesn't appear to be like a 25-year-old," she said. "He's confident, he's mature, and he's got a good head on his shoulders.

"He's done quite a lot of things. Plus he's had lots of jobs growing up like working in a café, working on the streets selling paella, chopping up meat in a butcher's van, and all sorts of jobs.

"So, you know, he has seen something of life… it's not as if he hasn't ever done anything. I think he's got a lot to offer."