It started out as a breakthrough project for a budding artist inspired by a photograph on a pub wall.

Eastern Daily Press: Andrew Tatham has spent 21 years researching a photo taken during the First World War. Picture: Ian BurtAndrew Tatham has spent 21 years researching a photo taken during the First World War. Picture: Ian Burt (Image: Archant)

But 21 years later Andrew Tatham has just opened the largest exhibition ever created by an external contributor at an internationally renowned museum which gives a completely new concept to the way in which military history is shared with its audience.

Mr Tatham, who has lived in the village of Fulmodeston, near Fakenham, for the past 10 years, started his epic trail for information and enlightenment back in 1994 and this autumn saw the fruits of his labours finally come to life at the In Flanders Fields Museum in Ypres, Belgium filling a hall space the size of two tennis courts.

The centrepiece is a group photograph of 46 men led by his great grandfather William Crawford Walton.

'I was starting out trying to become an artist and was looking around for ideas,' he said. 'I saw this really big First World War group photo of about 200 men on the wall of a pub and I wondered did they know what they were going into, these men casually squinting in the sun with their caps on the back of their heads?

Eastern Daily Press: Group photo at In Flanders Fields Museum in Ypres for Andrew Tatham exhibitionGroup photo at In Flanders Fields Museum in Ypres for Andrew Tatham exhibition (Image: Birger Stichelbaut)

'I had an idea of a painting, not just of that moment in time but seeing their parents and families behind them and their grandchildren playing in front. That got me thinking about my own family history in connection with the war.'

He remembered his grandmother showing him letters from her father from the trenches and he went ot the regimental history library at the Imperial War Museum to find out more. There he found the photo.

Seated in the middle of the group of men was his great grandfather, commanding officer of the 8th Battalion Royal Berkshire Regiment when they formed up at Salisbury Plain in May 1915.

After learning that nearly half were killed in the Battle of Loos at the end of September 1915 Mr Tatham, who was working as at IT consultant at a college of nursing, felt committed to finding out more about them, little knowing it would take more than two decades for his project to come to fruition.

'I moved on from having the painting idea to lots of other ideas such as the animated film that showed all their family tree from their birth to each of their descendents as they appear over time.

'The first tree starts to grow in 1864, my great grandfather who was the oldest in the regiment, and it follows from there as each tree starts growing and each branch is a new life as they start having children. But some of the trees disappear as they die.'

The key was finding as many relatives of the men as possible. As he was living in London at the time he spent days poring over records at Somerset House for wills and St Catherine's House for births, deaths and marriages.

There was no internet at the time and it was laborious work often looking through hundreds of records before finding one valuable clue which would put him in contact with their family.

'In one extreme case I found an address for a daughter of one of the men but I could not find a phone number so I wrote to her and heard nothing. Two years later I was on the Embankment and looking at a statue of Sir Wilfred Lawson and was thinking about the woman I had written to as she was the daughter of a Wilfred Lawson Clarke. The next day I got email from a firm of solicitors to say the lady had died and they were acting on her behalf and looking for her other family members when they found my letter among some paperwork. As a result I was able to find two uncles and there were descendents from both of these who were then able to inherit her estate.'

But after seven years of research Mr Tatham started to wonder what it was all for.

'I was exhausted,' he said. 'But I had made a film and I started showing it to more people and realised there was quite a lot of interest in it. There was now a lot of interest in genealogy and databases online.

'Family history and military history had always been done in a certain way but when people came to my presentations they always left surprised.

'I wanted to display it in a way that had never been seen before.'

During a trip to Ypres in 2008 he made a visit to the In Flanders Fields Museum and realised this is where he wanted to display his work. The director was so impressed with Mr Tatham's ideas he agreed to invest 100,000 Euros in the production of the exhibition and they agreed to tie it in with the centenary of when the picture was taken.

Mr Tatham, who had started working part-time in Fakenham library, set about creating the rest of his stunning artwork. Thanks to new technology he was able to rework the animated film in HD, complete 'stained glass window' portraits of each man and put together photo montages of each of the 46 using more than 1500 photographs he had collected from relatives over the years. He wrote a book to go with the exhibition in just 10 weeks.

A group photo of relatives was also taken with 20pct of all the descendents there including 50 direct descendents.

'It has not always been easy contacting people,' he said. 'Some were shy of me in the beginning but are now my greatest supporters.

'My next book will be on how I wrote it and the experiences I had along the way.

'People often leave doing family history projects until later in life and it is often too late to ask anyone about it.'

Mr Tatham would love to bring the exhibition to the UK but has come up against the barrier of people assuming it is only of interest to the families of those in the picture.

'But it is much more than that,' he said. 'I wanted to make people really think what the war was about. Everyone has something individual about them and this is examining it and thinking about your own personal history and how we all fit in to the world.'

Are you working on a First World War project? Email kathryn.cross@archant.co.uk