IT was only a battered old wristwatch but it was one of the most moving things I've seen on TV for some time.

Last night's The Trench Detectives on Five should have had a warning before it that viewers were likely to be deeply affected by the following 45 minutes.

In it, the team of enthusiasts were excavating on the site of Passchendaele, one of the most terrible battles of the First World War which claimed the lives of around half a million men.

Ninety years on the seemingly innocent landscape was still capable of springing surprises and reducing grown men to tears.

As part of their excavations, the Trench Detectives found a wristwatch and set out to try and trace its owner who lost his life in the Flanders mud.

Part detective programme, part history lesson, Trench Detectives is like Time Team with feelings.

The experts' clearly care deeply about the soldiers who bravely gave up their lives during the First World War and their determination to discover what happened to them and, if possible, give an identity to one of the thousands of unknown soldiers missing in action is touching.

Stark facts are all very well, but it is via personal items such as the wristwatch that history is brought alive for future generations. And the the nature of the sacrifices a generation made can truly be put into context.