I wish I could tell you that in David Jason's latest ITV1 drama, he plays a maverick computer hacker on the run from the Russian mafia, or a dashing international pianist preparing for one last recital before he retires. But of course, he's nothing of the sort. We know the kinds of characters Jason plays, and we love him for them.

Tonight it's Harry, a lovable London cab driver whose memories of the second world war are stirred when an old friend dies, leaving behind a bizarre request. Jason is an executive producer on the project, and it's his kind of drama, a touching, whimsical portrait of old age and its ghosts.

He's ably supported by David Warner as Harry's mate Frank. The two of them are surprised when their friend Albert calls them to his death bed and asks them to bury him in a field in Germany where the three men shared an unspecified trauma in 1945, one that bound them together, even though "We haven't had the guts to deal with it since."

What follows is a gentle caper involving a black cab, a coffin and a trip to the continent. There's a good deal of old-boy bickering between the leads, some mild black comedy and, underneath it all, a sad fable of war, death and memory.

This one-off drama might not have had the sexiest pitch ever: two World War II veterans honour their friend's dying wish by taking his body for burial in Germany. However, a cast led by David Jason, a nice splash of dark humour and the skilful unravelling of a mystery made it well worth watching.

The film kicked off with the dying Albert (Michael Jayston) asking his mates Harry (Jason) and Frank (David Warner) to bury him on the hillside near Berlin where they met the advancing Russian army. However, it was clear that the three men had a secret: something happened there that had haunted them ever since.

With Albert's death, the film edged into more farcical territory. Harry and Frank stole his body to prevent his cremation, and before long he was boxed up and strapped to the top of Harry's London cab for the road trip. Along the way, with the intervention of Vicki (Judith Hoersch), a young German hitch-hiker, Harry and Frank gradually came to terms with the events of 1945.

The mystery unfolded quite nicely, with clever editing reflecting the way memory works and inviting the viewer to piece together the tragic events. However, despite strong performances from Jason and Warner, the film relied too much on Last of the Summer Wine-style capers and creaky banter.

Worse of all, the plot leant on too many coincidences and contained too many moments that strained credibility. And after a moving climax, the clumsy revelation in the final minutes overshadowed the touching human drama of old men coming to terms with the past. A disappointing end to an otherwise engaging drama.

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Rock & Chips Review

Overall, Rock & Chips wasn't a total disaster, but it felt like a pointless excuse for John Sullivan to revisit his biggest success, now that David Jason has called it quits and present-day adventures are impossible.

There are many for whom the words Only Fools And Horses spell comedy gold. The Peckham-based misadventures of Del Boy and co habitually figure in all-time greatest sitcom lists and there can't be anyone left alive who hasn't seen David Jason fall through the bar at the Nag's Head. Like it or not, Only Fools And Horses has become part of British folklore. So as someone who never really got the whole lovely-jubbly lark, it was hard not to approach Rock & Chips without a touch of trepidation. This prequel from writer John Sullivan threatened to be 90 minutes of in-jokes about characters I never cared about in the first place, stuffed with references that would fly straight over my head. But knock me down with a filched feather duster, if it didn't turn out toan understated slice of bittersweet nostalgia.

The first mildly weird thing Rock & Chips had going for it was that Nicholas Lyndhurst was playing the dodgy criminal who turned out to be Rodney's dad. Given that Lyndhurst will forever be linked at the hip to the gormless Rodders, it felt oddly incestuous watching him seduce Mrs Trotter in a liaison that would climax with him fathering himself. Or maybe that was just me. There were more major plus points in the performances of James Buckley (of The Inbetweeners fame) as the young Del Boy and Kellie Bright as his sainted mother. Transcending the clunking staginess and looming sentimentality that threatened to scupper Rock & Chips at any minute, Buckley and Bright seemed beamed in from a classic black-and-white kitchen sink movie of the 1960s. They deserved a show all to themselves.

Though it was strangely unconvincing in its period detail - everything looked squeaky clean and lifted from the BBC props cupboard - and had more than the odd lapse into knucklehead farce, Rock & Chips was more than a mere vanity project for John Sullivan. Somehow it made me care about the Trotters in a way decades of Only Fools And Horses never came close to.