James Campbell, 35, claimed his mother Sarah Campbell had told him her estate would be “all yours” when she died. However, she died unexpectedly on a flight to the Canary Islands in 2015 aged 63, and her partner went to the High Court seeking a share of her estate.

Andrew Banfield, 66, who is disabled, argued that he had effectively been a husband to Mrs Campbell for more than a decade. He also claimed they became engaged in 1999, six years after the start of their relationship.

Mr Campbell denied that an engagement had taken place and claimed his mother’s feelings towards her partner had deteriorated to the point that she considered that Mr Banfield was “no more than a lodger” in her home in Thames Ditton. Yesterday Judge Paul Teverson disagreed. He conceded that Mr Banfield’s disability had made the relationship “more burdensome” for Mrs Campbell in later years.

He added, however: “I do not think it right or fair to characterise Mr Banfield as being no more than a lodger.

“The relationship continued to contain an element of mutual support, with the deceased making it clear to her close friends that she did not want to be on her own.”

Judge Teverson ordered that Mrs Campbell’s house be sold for at least £725,000 and half the proceeds invested in a home for Mr Banfield, which will revert to Mr Campbell on his death.