Aliens exist and they could be living among us, the first British astronaut into space has said.

Dr Helen Sharman, who went into space 28 years ago, said it is without a doubt that “all sorts of forms of life” are alive in the universe - but perhaps we “simply can’t see them” as they are so different to humanity.

“Aliens exist, there’s no two ways about it,” Dr Sharman told the Observer Magazine. “There are so many billions of stars out there in the universe that there must be all sorts of forms of life.

“Will they be like you and me, made up of carbon and nitrogen? Maybe not. It’s possible they’re right here right now and we simply can’t see them.”

In 1991 Dr Sharman became the first Briton in space after hearing a call for astronaut applicants on the radio while driving home from work. Despite fitting the criteria she almost decided against applying for the programme, but decided to chance it.

“Self-belief and a can-do attitude changed my life,” explained Dr Sharman. “I ticked all the boxes, but thought they wouldn't choose me so I wouldn't bother. By the time I got home I'd realised that if I didn't actually apply, then they couldn't choose me.”