The 54-year-old, who played Tom the Innkeeper in ‘Harry Potter And The Prisoner Of Azkaban’, suffered a broken neck and a punctured lung in the crash.
He also has 15 broken ribs, breaks in his right leg and fractured breastbones.
His wife Laura took to Facebook to share a photo of her husband in a hospital bed and asked fans to “hold good thoughts” for him.
“This is Laura here,” she wrote. “Now that his family have been informed, Jim has asked me to let you all know that he was involved in a serious car accident yesterday, a head-on collision,” she wrote.
“He’s currently in ICU intensive care. He has 15 broken ribs, fractures in both breastbones, a punctured lung, multiple breaks in his right leg, and a broken neck.
“He’s had two blood transfusions so far and is about to go in for his first surgery. This is for real, not a movie role. Please hold some good thoughts for him as he fights his way out of this.”
Fellow entertainers took to Twitter to wish him a speedy recovery...
The Essex-born actor, who trained at the Royal Academy of Dramatic Art, also co-wrote and starred in the Bafta-winning ITV series ‘The Sketch Show’.