Bill, 73, is visiting a "reminiscence library", set up by Westminster council to help the borough's 1,500 sufferers of Alzheimer's and dementia. Like the rest of the elderly visitors here, he is struggling to recall his experiences during the war: each sentence is begun clearly enough, but the words soon run into an incoherent jumble.
In his case, the helmet does not help: he seems as unfamiliar with it as with the era it represents. Instead, he goes further back in his memory, talking about his father's job as a timberman in Ireland at the turn of the century.
It was Dame Shirley Porter's swan song as the council's leader to oversee the establishment of a reminiscence library. It is based at the Tresham Resource Centre, Marylebone, and opened last December. It is the only council-run facility of its kind in the country. It houses more than 500 artefacts, mainly from the Thirties, Forties and Fifties, which staff use to help sufferers to recall their past and relive the excitement of occasions such as the 50th anniversary of VE Day.
The library's care staff run two reminiscence classes a week for 16 elderly sufferers referred by social workers via GPs and consultants. They do not promise dramatic "awakenings", although they hope that the specially designed Thirties kitchen will jog a few memories.
Isabella, 87, suffers from Alzheimer's but still remembers the war as if it were yesterday. She recalls driving her uncle, a naval officer, and his wife to Aberdeen so that they could watch him set sail in his new ship. "We drove past Balmoral," she remembers, "and stopped the car so we could see the Queen's dogs. They were two Cairn terriers; one was called Doogie and I forget the other's name."
Isabella can vividly recall the details of her life as a young woman. But ask her where she lives now and she insists her home is still seven miles outside Aberdeen, even though she has lived in Westminster for more than 10 years. Pressed to explain further, she complains of being "all confused".
Paul Huggett is the care worker taking this reminiscence class. Each time the class meets, Mr Huggett has to make fresh introductions because in the space of a few days they have forgotten who he is. "Many people with Alzheimer's have very poor short-term memories but their long-term memories are still intact," he explains. "We are trying to tease out those memories."
When he shows them the gas mask, recollections come flooding back to many in the group. The clothes mangle revives old class divisions: Millie, 80, remembers "breaking her back" using it, while Isabella tells the group that those sort of cleaning chores were left to her maid.
No such divisions are caused by the library's giant spinning-top. As the group sit around taking turns to spin it, they become immersed in the happiness of second childhoods.
Alzheimer's sufferers can talk for a long time before they say anything to suggest they may have the disease. "It's hard for them to accept the condition: they tend to explain it away by simply saying they've had an accident," says Mr Huggett.
For the sufferers of severe dementia, the problem is not that they have forgotten the war but that they have completely lost all social orientation. "Sometimes they forget to associate light with day and dark with night, which means they might then go shopping in the middle of the night," says Mr Huggett.
Lee Sims is manager of the Tresham centre and it was his idea to use a £10,000 grant from the Westminster Charities Trust to build the library. Before it opened, he spent nearly two years trawling local markets and antique shops to handpick the 500 artefacts,
Among the items is a large record collection. Music is a useful tool because it can find pathways to memories that may have been buried for many years. "Not everyone likes the typical music-hall favourites of the Thirties and Forties such as 'Don't Dilly Dally' or 'Pack Up Your Troubles', so we try to provide a wide choice of music," says Mr Sims. "Sometimes it may just be the colour or shape of an old 78 which jogs the memory."
He believes that reminiscence work, using these kind of artefacts, can enhance an old person's self-esteem and reassure them that the past still exists. "It can help them make sense of their own confused past. It gives people something positive when so many other aspects of their lives have failed."
Occasionally, he says, it can be painful. "Not all memories are pleasant ones, and when we do this reminiscence work we don't know what may emerge."
He remembers one old woman who was very uncommunicative and used to wave her stick aggressively. "One day I noticed she was looking at an old family photograph and asked if she would show it to me. She ended up talking at great length.
"By using the picture she had been carrying around in her handbag for many years, I had found a way of working with her. Now she talks much more freely and no longer waves her stick at people."
But Mr Sims says the care team only reaches the tip of the iceberg. "In Westminster, we manage to reach about 300 of the Alzheimer's and dementia sufferers," he says. "Most of the other 1,200 are suffering without really knowing whether or not they are ill."
Anyone in Westminster can make use of the library. Its staff hope that by encouraging other groups concerned with dementia to borrow the artefacts, the therapy of reminiscence will reach some of those who still suffer in silence.Reuse content