Only Fools and Horses star David Jason is returning to BBC TV but this time as a hero of World War One.

Jason plays Captain Frank Beck in BBC One's powerful drama for Remembrance Sunday, All the King's Men.

The film, which boasts a star-studded line-up including Dame Maggie Smith, shatters eight decades of myth surrounding the "vanished battalion" of King George V's Sandringham estate.

Dame Maggie Smith plays Queen Alexandra in an all-star cast

Even for the award-winning Jason, the chance to star in such a major piece of work - and set the record straight - was an opportunity not to be missed.

"Although there have been many stories about the World War One, none compares with this heart-breaking story of the Sandringham Company.

"They were the King's own regiment. The Sandringham community was like an extended family. It was a story that needed to be told," Jason explains.

David Jason says the story of the Sandringhams just had to be told

His character Beck was the ageing land agent at Sandringham - the Norfolk estate of the king - whose "rag-bag of servants, grooms and gardeners" were transformed into a "superb fighting force".

On 12 August 1915, as captain of the fifth battalion of the Norfolk Regiment, Beck led his green young soldiers across the arid expanse of the Suvla Plain in Gallipoli - straight into a wall of enemy Turkish fire.

Beck's regiment walked into a fierce and fatal battle

Suddenly, the men were embraced by an ethereal yellow mist. Eyewitnesses talked of the cloud carrying the men heavenward to safety. But whatever occurred, the Sandringhams were never seen again.

Now, after 80 years of romanticism, All the King's Men reveals that the fate of the men was ugly and cruel. So much so, that for reasons of national pride and morale, the truth was kept hidden.

But enthralling though the events of All the King's Men undoubtedly are, Jason stresses that the underlying tale of loyalty and courage is what truly makes the drama of the piece.

"It is so important to remind ourselves that people gave their lives in tragic circumstances so that we could all be here today.

"I think that telling a story like this can only serve to say that when these terrible things happen it is ordinary people and families that are affected. Ordinary people make heroes - they are not just born with an H on their heads," he says.

Beck insisted in going to war to support his men

The epitome of this heroism is undoubtedly Beck. Despite the pleas of the king, for whom he was a particular favourite, Beck refuses to let the men he has nurtured go to war without him.

Assuming the role of a man of such integrity was, says Jason, a huge honour. But he admits he felt burdened by the task he had taken on.

"I have always played characters that are invented and have been able to fiddle about with them because they have existed in my imagination. Frank Beck, on the other hand, is a real character, the first one that I have played.

David Jason says playing Beck was harrowing

"The responsibility to the character, to the family and to everyone concerned at Sandringham was really heavy at times. I found it daunting - but daunting in a good way," he explains.

The whole of the Sandringham community were close to the royals

Jason also confesses that the Beck family were tentative about his suitability for the role - one that is so far removed from his best known characters. But by the end of a lunch with Beck's grandson, Edward Hunter, Jason had gained their blessing.

"As we were leaving, Edward said 'Well, when I first heard you were going to play this part I thought absolutely not - there was no way you could possibly do it. But now I have met you, I think you can'," Jason recalls.

The seven-week shooting schedule - much of it in the 100 degree heat of southern Spain which doubled for Turkey - left 57-year-old Jason "knackered".

The three-year battle, of all involved in the production, to bring the findings of writer and former policeman Nigel McCrery to the screen has been an additional strain.

The soldiers were unprepared for the intolerable conditions

Emotionally too, he says he is too bruised to want to take on a new part - let alone in a comedy - for some time. But he is adamant that the legacy of his hard work has made it worthwhile.

"I am a very great pacifist which is one of the reasons why I wanted to do this. But when you make something like this you are trying to get home that if you have to send blokes to war, make sure they are looked after.

"It was particularly obvious in the 14-18 war that nobody was serviced well - on any side. But I am always consistent in that there should be other ways and sometimes you have to stand up and be counted."