There are “Ulster Says No” cigarette lighters, Orange Order Christmas decorations and banknotes mocked up with an image of Gerry Adams at the time of the 2004 Northern Bank heist in Belfast. In all, Peter Moloney has collected 40,000 such artefacts, all culled from decades of political turmoil and bloody strife.

Moloney, a retired London-based architect, has spent 50 years accumulating the largest array of memorabilia relating to the history of the Troubles in Northern Ireland – a labour of love that began when he was just 15. And this month he finally packed up the unique historical treasure trove and sent it back to Northern Ireland, where it will go on public display. The exhibition will coincide with what is regarded as the 50th anniversary of the beginning of a bloody chapter, sparked by the Catholic civil rights movement of the late 1960s.

“I felt that it was time for it to go home,” said Moloney who for decades juggled his day job working as a project manager for local authorities with frequent trips across the Irish Sea to build up the collection.

As the years passed, it became an archive covering Bloody Sunday, the hunger strikes, peace initiatives and other events. It took over the nooks, crannies and garage space of the architect’s home in Camden.

In the hands of the Tower Museum in Derry – which Moloney chose in spite of international interest from institutions such as the V&A and the Guernica Peace Museum in the Basque country – he hopes that what he has created will be “a motivator for peace and reconciliation and common understanding”.

Giving away the collection has not been easy, particularly as it has been accumulated at considerable cost and, during some of the conflicts’s most fraught times, personal risk. “I got arrested a lot in the years when I was going around collecting things or taking photos, although the longest I was held was 24 hours,” he recalls.

“Typically, the police would get very excited when they would find, for example, republican propaganda in my bag. But then they would dig deeper and find the loyalist stuff, and that would confuse them. I would say that it was for an academic book that I was going to write, and that would appease them somewhat.”

Facebook Twitter Pinterest 1974 bus ticket bearing the number of a confidential police phone line on which the public could report illegally held weapons. Photograph: The Peter Moloney Collection

On other occasions the unwelcome attention was more menacing. Moloney – who was born in the Republic of Ireland and raised in London – tells of being followed on by suspicious loyalist paramilitaries in the dark days of the 1970s. He emerged unscathed when a friendly shopkeeper, who had recognised him from previous excursions, gave an alibi for what he was doing in the area.

Moloney decided to give away the hard-earned memorabilia three years ago, following an exhibition in Northern Ireland to which he contributed a bus ticket emblazoned with a confidential police telephone line on which members of the public could report illegally held weapons. “Nobody remembered the bus ticket, yet millions must have been produced. It was the impact of that as it travelled around that was the final catalyst for me in terms of thinking that it, and the rest of the collection, would be of more use in the north.”

Aside from curiosities such as the bus ticket, the archive comprises some 3,000 political journals, 2,000 books, and thousands of posters, badges, cartoons and stickers.

“I always kept it at home. One of the things [I picked up] from studying architecture was that I became very adept at the use of space, whether it was putting things under beds [or] in wardrobes,” recalled Moloney.

The new custodians of the collection admit to being taken aback by its sheer scale. Roisin Doherty, curator of the Tower Museum, said: “I was just amazed at the sheer amount of objects: this is not just a paper-based archive – it is normal, everyday artwork, banknotes, leaflets, commonplace items that everyone saw, but because Peter decided he was choosing that object for the collection, it gives them a special significance.”

“It took a while for us to get around the expanse of it. It has just arrived now in boxes, and there are quite a lot of them, so the exciting thing is about getting to see the actual, physical items.”

Doherty, who says that her own children have no concept of the Troubles, is also very clear on the role today of what Moloney has created. “The fact that there is a collection there now – almost a silent voice, there to give testimony, to say, yes, this was what life was like, this was the norm and we can’t forget it – is extremely important.”

“This year is so significant, too, and ... we can now use [Peter’s collection] to create an awareness and dialogue, which will go on for years to come.”

Moloney, who has lectured widely in the UK, Europe and the US on the conflict, will deliver a talk at the Tower Museum on 10 April. Meanwhile, he has started collecting again from scratch. “It’s an ongoing process. I will probably be buying less and doing a lot more photography.”