January 2012:  I had all but finished the book to accompany Dan Snow’s  TV series on the archaeology of the Second World War. The ‘on-site’ research took  me  on  some of the digs, including one  to Somerset to watch the excavation of a  Spitfire that crashed at Crewkerne.  Although the Canadian pilot baled out, I was left thinking of all the young airmen, again on both sides, who were not so lucky and who would have been at the controls, just behind the engine, when their crippled aircraft crashed into the ground at several hundred miles an hour. We think we know all there is to know about the Second World War, but it takes the physical evidence, in combination with all the other sources, to round out the story and bring an emotional understanding.

Shortly after that dig, I got to meet the son of that pilot when he came over from New York.

The series went out on the BBC. Actually, it was a bit of a mess because at first we were told it was going out on BBC1 or 2, then it was only for BBC NI (okay if you have satellite TV), then a 1-hour special was screen on BBC1, and finally the whole series was screened at short notice over three nights.  A Candian production was also made.  

As well as digs to recover crashed aircraft and visits  to both famous and forgotten sites, it featured dives on sunken U-boats and merchant ships.  The images  in the book are excellent. There are even some of my photographs - of pillboxes... Jennifer Veall, the picture editor, has done a wonderful job, and so has the copy editor, Chris Westhorpe. Tie-in books are necessarily written rather more quickly than most other books, so a good copy editor like Chris is such a bonus. Editors are a pain because they nit-pick and you feel right up against the deadline,  but afterwards, when the stress is all finished and the book is in the hand,  you have to admit that it is a better book for that rigorous scrutiny.

This was my first TV-tie-in (probably the last!) , so as well as doing my own research and writing I had the chance to watch the team from Derry-based 360 Production  and, of course, Dan Snow, in action. You have to keep alert: stay out of the way of the cameras, and keep the voice down. If they have to raise the sound level in the studio it can bring up sounds from a surprisingly far distance, especially in a rural area. Dan was amazingly professional. His responses  to camera were always unrehearsed, and even at the end of a day’s filming he was full of enthusiasm. He also had the ability to spend a day digging in a hole and yet emerge clean and tidy.

The book isn't quite the same as the TV series. I have been able to research the stories in more depth and bring in more of the background. You don't realise, until you see the actual script, how little words there are in a one-hour documentary.  This really is a case in which the images tell the story and the voice-overs etc expand and guide the viewer through the images. So, for example, the team carried out that dig  at Crewkerne to see what could be recovered of a Spitfire that crashed in 1942 after running out of fuel. I have been able to tell the story of the young Canadian pilot, both before and after the crash - and a remarkable career he had! I'm very grateful to his son for the help he gave and the images he let us use. The team also  filmed at Bois Carrée, one of the infamous lauch sites for the V-1 bombs that caused so much destruction in London, so I broadened out the story to include the bomb-chasing exploits of 41 and 91 Squadrons RAF and the self-sacrifice of one of their pilots, a young Frenchman, a week before he was due to marry. As a third example, I included quite a lot of material on the Defence of Britain in order to bring the Northern Irish stories into the wider context of anti-invasion preparations. I think it is important that tie-in books give you something extra, rather than simply being a copy of the TV series but without the moving images.

It's a fascinating series of programmes, covering ground that will have been new to many people and in a format that is easily accessible without being patronising.  One thing had worried me: would it be yet another of those series where so much time is spent telling the viewer what they will see, repeating words spoken to camera by those who are interviewed, and then recapping every five minutes?    I have lost count of the number of potentially interesting programmes I gave up watching because they drove me to distraction with the constant repetition.  Dig WW2 wasn't like that.

During my research into  the Defence of Britain I discovered the Spigot Mortar Emplacement. It doesn't look much, but thousands of these were distributed to the Home Guard to be located in pits dug in positions covering canal bridges, crossroads and other strategic points. Its purpose was to act as a support and pivot for the portable Blacker Bombard, an anti-tank or anti-personnel weapon likewise issued to the Home Guard. When the weapon was fired, a spring in the barrel pushed a spigot into the bottom of the mortar shell, causing a detonation that fired the shell. Fine in theory, except that the Bombard was a muzzle-loader, and its anti-tank range was 100 yards or less. Home Guard officers were not impressed with a  weapon that would have to be reloaded at such close range, right under the eyes of the enemy. However, away from the Home Front and reinvented as the the PIAT (Projector, Infantry, Anti Tank), it became the infantry's  anti-tank weapon par excellence in  several theatres of combat, and was used by at least seven Victoria Cross winners. The abandoned  emplacements can still be found dotted around the British countryside.