According to The Sun, Barbara Brand, 71, was travelling in the back of the comedian’s chauffeur-driven Audi A8 when it collided with a Vauxhall Astra near Brentwood, Essex, on Thursday morning.
In a video on social media, Brand said she was “vulnerable” and had “only finished chemotherapy a month ago”.
Addressing the camera, he said the accident had been “really serious”, and his mother had sustained “what are called poly-traumatic injuries”.
“That means numerous, life-threatening injuries,” he added.
Saying that he could not “imagine performing at the moment, because I feel too sad”, he said he would be unable to do the rest of his tour.
“I apologise but obviously it’s circumstances beyond my control,” he said.
“If you’ve got tickets, they’ll be refunded or possibly rescheduled.”
Brand said the accident had brought home the “importance of people you love”.
He said he had also been reminded of the “importance and significance of the NHS” which has saved his mother’s life on “six occasions” after she suffered from cancer half a dozen times.
To see the way in which the medical profession operated was “phenomenal”, he said, describing the health service as “the soul of this country”.
Those working within the NHS are “benevolent, and kind, and doing something valuable”, he added.
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Brand said he would be off “social media for a while”, and thanked people for their “positive, beautiful messages”.
He finished by asking his followers to “please continue to keep my mum, Barbara Brand, in your thoughts and in your hearts”.