The youngest MP elected to parliament in more than 350 years has said she may not stand for a second term because she hates Westminster and so little gets done.

Mhairi Black, who was 20 when she won the seat of Paisley and Renfrewshire South for the SNP from Labour’s Douglas Alexander in 2015, says she finds parliament “depressing” and “defunct”.

She told the Sunday Post she had not got used to working in Westminster: “It has been nearly two years and I still hate the place,” she said. “It is depressing. It is the personal elements – it is a pain to come up and down every week and you are working with a number of people you find quite troubling.

“Professionally, it is more just that so little gets done. It is so old and defunct in terms of its systems and procedures – a lot of the time, it is just a waste of time.”

Asked directly by the newspaper if she would see re-election, she answered: “I don’t know.”

She added: “I think you should only stand in politics if you think there is a need for you to be in it.”

But she said she was relaxed about her future: “I have a habit of falling into things. I fell into university, fell into this and have fallen into most jobs I’ve had.”

In the interview the lesbian MP revealed that despite her dislike of Westminster she had made friends there, including one Tory “boyfriend”.

“I get on quite well with a lot of the Labour old guard and quite a few Tories actually,” she said. “There is my boyfriend – Jacob Rees-Mogg. He’s my favourite. It’s the kind of place where, if you are reasonable with folk then they will soften a little.”

In January the Labour MP Jamie Reed quit as MP for Copeland in west Cumbria, saying he felt he could achieve more for his constituents working for Sellafield, the area’s biggest local employer, than in parliament.

In 2015 the Rotherham MP Sarah Champion told the Guardian she would serve a maximum of two terms because the life of a politician was a “living hell”.

“My plan is to do another five years and then go,” she said. “I don’t think it’s healthy to be there for too long. Because the longer you’re there, the more distant you get from reality.”

Their approach was a marked contrast to that of their Labour colleague Sir Gerald Kaufman, who died last month aged 86 and was determined to serve parliament until his dying day.

“He refused to retire, and did not react well to suggestions he might consider doing so,” said the Stalybridge and Hyde MP Jonathan Reynolds after Kaufman’s death. “When the new set of police commissioners and mayors were created, he told me no one should be allowed to resign from parliament to contest them as being an MP was the highest office available (I didn’t quite agree!).”