Russell Brand has cancelled the rest of his tour after his mother sustained "numerous life-threatening injuries" in a car accident last week.

The Forgetting Sarah Marshall actor scrapped a show on his comedy tour on Thursday for "personal reasons", and it later emerged that his mother Barbara had been involved in a road collision.

Barbara had been on her way to her son's house to babysit his and wife Laura Gallacher's 17-month-old daughter Mabel, when a Vauxhall Astra crashed into the Audi A8 she was being driven in, and she was reportedly pulled out of the damaged vehicle screaming.

Russell took to social media on Monday to post two videos in which he explained that he will not be continuing his comedy tour, which had five dates remaining.

"My mum's been in a really serious road accident and has sustained what are called poly-traumatic injuries, that means numerous, life-threatening injuries, so I won't be able to do the rest of my Re:Birth tour," he said. "If you have tickets they'll be refunded or possibly rescheduled but I can't imagine performing at the moment, I feel too sad and too connected to this. I apologise but obviously, it's circumstances beyond my control."

In the video, he revealed that his "vulnerable" mum had only finished chemotherapy a month ago and had battled cancer six times. He also shared that the situation had made him realise the importance of the U.K. National Health Service (NHS).

"So again, sorry to convey this sad news to you. I won't be on social media for a while," the 42-year-old concluded. "Thank you for all your positive, beautiful messages (and) prayers – for those of you for whom that is meaningful and appropriate. Please continue to keep my mum in your thoughts and in your hearts. I'm sending lots of love to you and gratitude, cheers, I'll see you all soon, I hope."

Barbara's chauffeur has been released from hospital. A man in his 40s was arrested in connection with the crash on Friday.