When Jonas Armstrong was collecting his BASSC Certificate in Stage Combat at drama school, little did he know that those skills would one day come in handy to land him his biggest role yet.

As legendary English folk hero Robin Hood, Jonas battles the evil Sheriff of Nottingham and his cronies in action-packed scenes of scintillating sword fighting and breathtaking archery. But with a mere whirlwind week to prepare for filming, he was thankful he'd paid attention to his combat lessons at RADA.

"When I got the job I was over in India filming," Jonas reveals to Judy Leighton, adding that he almost didn't bother going to the audition as he was due to leave for India just a few days later - and he didn't think he stood a chance anyway! Luckily his agent convinced him to turn up and his low expectations even helped.

"I wasn't as nervy as at some auditions and I think that put me into a good mindset because I didn't have the pressure. Then when I got the part I was amazed - gob smacked even - but ecstatic because it's such a well-known and well-loved character, everybody knows Robin Hood."

But being fully occupied in India, there weren't many opportunities for Jonas to brush up his archery and sword-fighting skills, although he was able to do some training.

"I was in the gym every day - I have quite a slight build anyway so I was trying to eat a lot more and go to the gym and go swimming," says the six-foot-tall actor. "Once I got to Budapest [where Robin Hood is filmed] we just had a week until filming started. We were on the horses every day and practising archery and sword fighting and unarmed combat every day, so it was quite difficult. Then at the end of the week they threw me a sword and said, 'Right, now look amazing with it!'"

And it's not just any old sword, either. "It's a Saracen sword from the Middle East, so there's a very specific way of fighting with it," Jonas explains. "I think I've really come on with it over the series."

The 25-year-old, who was born in Ireland but grew up in St Annes in Lancashire, is also now a bit of an expert horseman too. "It's a really good buzz when you're stuck on a horse and told to fly around one-handed with a bow in one hand, shouting orders - that's brilliant and I really enjoy that," he grins engagingly. "They give me free rein on a horse now because I have got to be on them a lot more, so they gave me more time to learn and paid extra attention to me. I'm the only one who is allowed to gallop on a horse!"

That's the special status reserved for the hero - though Jonas says that in this version of the robbing-from-the-rich-to-give-to-the-poor legend, Robin isn't always in the right.

"He's a flawed character and he has got downsides to his personality," admits Jonas. "He's not just this do-gooder who hasn't got a bad bone in his body - he does have some bad aspects to his personality. He can be sidetracked and become clouded by his own agenda and his personal issues, which can strain his relationships with the outlaws. He's quite an arrogant character, rather vain and he can be self-centred - but overall the rounded Robin is essentially a very decent, good, good-spirited person."

Jonas, whose previous TV roles include student Anthony in Teachers and thrill-seeker Pete in gritty cop drama Ghost Squad, both for C4, admits he likes Robin's flaws and that they make him a more interesting character.

"He has to have these darker moments - it makes him human. People may say he's supposed to be this dashing, swashbuckling hero and he has got that, but there's another side to him too so hopefully that will come across as well. It also makes him different to previous Robin Hoods who have been more out-and-out heroes."

Another surprising aspect of this Robin is that he's also a bit of a womaniser...

"He does think he's got a way with the ladies!" laughs Jonas, hastily adding that his old flame, Marian, would certainly not agree.

"She just sees right through it. She says in the first episode, 'Seven years and you're still peddling the same old drivel - does it ever work?!' So she's not interested. Their relationship is frosty..."

It seems Marian still hasn't forgiven Robin for deserting her to go and fight for King Richard.

"They were sweethearts and then Robin went off to fight for King and country in the Holy Land," Jonas explains. "Obviously Marian was a bit miffed when he decided to go, going off there for glory rather than staying with her. He comes back and just thinks he can pick up where he left off and get her to fall back into his arms but it isn't that easy. Which makes it all the better! It's about him trying to woo her."

Jonas picks out this storyline as his favourite of the series.

"I think it is a love story," he says adamantly. "There's also the battle between the good and the bad, the tyrant and the hero, which is obviously Robin and the Sheriff, and there's loads of action that will engage an audience - action sequences and fighting and stunts and everything else; but the love triangle between Sir Guy of Gisborne, Marian and Robin is the most obvious through line of the whole thing, I think, and the one I tried to concentrate more on."

And it's not just a straightforward choice between hero and villain for Marian.

"Gisborne is a better prospect because he has security and wealth. Robin would have had that but he decided to become an outlaw when he came back," explains Jonas. "But hopefully the viewers will go, yes Gisborne has got all that but he hasn't got the thing that Robin has got, which is the excitement that he can give her and also, of course, the love - she doesn't love Gisborne, she just sees him as a breadwinner."

Back in the actual time of the story, though, Marian wouldn't have had much of a choice - in those days it was the men who decided. But the legend has been updated to appeal to today's more sophisticated audience and, says Jonas, is quite modern in its feel. Its contemporary slant has led to it being dubbed Robin Hoody - much to Jonas's amusement.

"People have been on about this but I thought it was obvious to have Robin Hood in a hood - that's his name!" he says wryly. "I always thought that he would have a disguise, and that's the hood."

But while the series threatens to make the hoody trendy again, this may not yet be rehabilitation for the much-maligned garment. As Jonas adds with a twinkle, "Don't forget, he is an outlaw!"