The star of the original Yorkie chocolate bar adverts is facing jail after admitting killing his terminally ill wife.

Stuart Mungall, 71, denied murdering former actress Joan, 69, at their home in Tooting, south London, in December last year, but the prosecution accepted his plea of guilty to manslaughter on the grounds of diminished responsibility caused by depression following the strain of caring for her.

The Old Bailey judge was asked by the prosecution to jail Mungall because Mrs Mungall, who had only a matter of months to live, had not asked to die. Mark Dennis QC, for the prosecution, said Mrs Mungall, who had a degenerative disease, told a nurse the day before her death that she was "taking it all in my stride".

Mrs Mungall was smothered with a pillow in what Mungall saw as a "mercy killing". He then took tablets to try to kill himself. He told police: "At last Joan is out of pain and free from it all." Mungall found fame in the 1970s as the handsome lorry driver in the ads for the chunky chocolate. He went on to appear in Casualty, The Bill and other television series. The couple were described as being devoted to each other. Mungall was said to have shunned offers of help in looking after his wife, although she received medical support at home.

The prosecution asked for a sentence of less than a year and said Mungall had served the equivalent of six months in custody before being granted bail. But the Recorder of London, Judge Peter Beaumont, said he wanted to explore all the possibilities. He told Mungall: "You present a difficult sentencing exercise because you took the law into your own hands and you took a life in doing so."