Dame Sheila Hancock said she is grateful to those scouring the streets of London looking for her “most treasured possession” described as having “huge personal importance” to her.

The British actress, 90, lost a sentimental gold chain holding four wedding rings belonging to each of her parents and her two marriages to the late John Thaw and Alec Ross.

Sharing several posts on Twitter, her official account was offering a reward for finding the necklace as the Metropolitan Police “no longer deal with lost items”.

A statement said: “Sheila is so grateful to everyone sharing the posts about her lost chain with the wedding rings.

“It hasn’t been found yet but she sends heartfelt thanks to everyone trying to share news for her.

“If anyone does find it, it is of such huge personal import(ance) to her.. plse contact us.”

An earlier tweet read: “CCTV suggests this necklace w. the 4 wedding rings was lost round Haymarket W1.

“The police no longer deal with lost items so even if someone went to hand it in there is no central system to find it.

“She is desperate to have this personal treasure back.”

Pictures of Dame Sheila with the chain around her neck were also tweeted, which said the actress is “heartbroken to lose her most treasured possession”.

Dame Sheila, who was married to the actor Thaw before his death in 2002, started her career in the theatre, finding success in both the West End and on Broadway.

Her career flourished with comedy performances on the BBC, with roles in sitcoms including The Rag Trade, Mr Digby Darling and Now Take My Wife.

In 1972, she landed her own series, But Seriously, It’s Sheila Hancock.