In her role at the local Royal British Legion Joy Widdowson campaigned for veterans in their twilight years to at last receive the medals to which they were entitled.
She lived in North Wales and Shropshire before moving to Wolverhampton and became an active member of Wolverhampton's SSAFA – the Soldiers, Sailors, Airmen and Families Association.
Also known as Joyce, she died on December 8 shortly after her 87th birthday and her funeral is being held at West Chapel, Bushbury Crematorium, at 2.15pm on April 15, after extensive but fruitless efforts to find relatives.
Friend Jan Timmis, who is organising the funeral, said: "She was quite an enigma, was Joy. She kept her life quite private. She did not have any family that we have been able to trace. She was married and divorced but we have not been able to track anybody down.
"She was always known as Sister Joy because of her nursing career."
As a nurse in London she cared for both Lord Callaghan and his wife during their later years and also acted as his personal assistant. She moved to Wolverhampton shortly before his death, which was in 2005.
Miss Widdowson had previously been part of the team that nursed other public figures and their relatives, including the mother of former Liberal leader Jeremy Thorpe and poet Sir John Betjeman.
Jan said: "She told my husband that she did nurse George Best at some point in her life."
She was born in Manchester, and her parents then had a bed and breakfast in Llandudno and Joy moved with them. They then seem to have bought a bungalow in Prestatyn. Jan does not know how Joy came to be in London.
She lived for a time in Cleobury Mortimer and on her move to Pendeford, Wolverhampton, she became involved in the local armed forces charities.
Jan said: "She was the legion's welfare officer, and would call the veterans 'the boys' – they were in their 80s and 90s. She would have them round for Christmas dinner rather than them being on their own.
"One of her great concerns was veterans who had not received their medals for various campaigns. She spent her whole life valiantly trying to make sure these veterans had their medals before they passed away. I have spoken to numerous people who are so grateful to her.
"She was always more interested in you than in telling you about her own life. She gave so much to other people. It's quite staggering really what she achieved."
Among those at the funeral will be Deputy Lord Lieutenant Sylvia Parkin, Captain Richard Jones of the Mercian Regiment, RBL standard bearer Graham Morris, and Fred Bunce will read the "they shall grow not old" excerpt from the Ode of Remembrance. A bugler will play the Last Post.
"I'm hoping, although it's a bit up in the air, that there will be a guard of honour from the Royal British Legion when she comes into the crematorium."
Jan says Joy did not have any siblings, and always used her maiden name Widdowson – she does not know with any certainty what her married name was.
Another friend, Liz Turner, said: "She was just full of life, bubbly, enthusiastic, and nothing was a bother. Everybody else was important to her.
"In her life she had many incarnations and many amusing revelations.
"Her family was from Manchester and her dad was in the RAF. She was very proud, and that's where her RBL background comes into play.
"She was a private nurse and I have got the Tower of London beefeater bear that Lord Callaghan gave her for looking after him when he was poorly as a parting gift. She passed the bear on to me before she died."
In March 2013 a picture of the late Lord Callaghan was hung in Wolverhampton Civic Centre, in an event organised by Joy. It came almost 34 years to the day after he officially opened the building.
She had contacted Julia, his youngest daughter, who sent a print from the portrait of Lord Callaghan that hangs in the hall of the city of Cardiff which he represented in Parliament.
Miss Widdowson commissioned a cross stitch background to the framed picture with a sun in a corner as a reminder of his nickname – "Sunny Jim."