YOUNG ACTORS in today’s social media-driven society face much tougher challenges than previous generations, according to stage and screen star Gwyneth Strong.

“Young people, not just actors, have it really tough today,” she explains. “The unending exposure they face on social media – it’s dreadful. I feel very grateful I didn’t have that level of scrutiny when I was starting out.”

Strong, who is appearing in the Agatha Christie classic The Mousetrap at Edinburgh’s Playhouse this week, admits she was unprepared for the level of attention which accompanied her most famous role. The London-born actor played Cassandra in the legendary TV sitcom Only Fools and Horses in the late 80s and early 90s.

“I had a little of it, because I had been a child actor, but back then you tended to get some attention for the job you were doing and then it all calmed down and went away – there was no Twitter or Instagram to keep it all going,” she explains. “But of course, Only Fools and Horses just never went away.”

She adds: “I remember taking my son out for a walk in his pram – he was six months old, this was my first job after having him. It was a Monday morning, and the show had aired the previous evening. I’d never experienced anything like it and I realised I’d never walk my local streets in quite the same way again.”

From an early age, says Strong, she was interested in performing. “My father was a TV director, my mother worked in production for the BBC so I understood that television could be a job for an actor,” she says.

“My parents didn’t want me to do it, just as I didn’t want my children to do it. But somehow, my photograph ended up with a child acting agency and that was that. I had to battle my parents over it for a while, but eventually it was fine.”

Strong, who is married to fellow actor Jesse Birdsall, jokes she had more success with her own children.

“I really didn’t want them to go into acting, I wanted them to have much more stable careers,” she says. “But I don’t think either my son or my daughter really wanted to act. They saw both their parents in the industry and thought – okay, it’s fun a lot of the time, but sometimes, it’s really not…”

Strong’s first job was at the Royal Court Theatre when she was 10 years old. She appeared in several shows throughout the 70s and 80s, including The Adventures of Black Beauty and Edward the King, alongside Felicity Kendal.

Life changed, however, in 1989, when Only Fools and Horses writer John Sullivan decided to introduce female characters to the popular show for the first time.

“I was nervous about joining the show, although at that point, it was only supposed to be for a couple of episodes,” she says. “I had no idea it would be as long-running as it was.

“I don’t see joining Only Fools and Horses, or a classic play like The Mousetrap as any different from anything else I do. Yes, I have a responsibility to it, but I’m pretty serious about everything I do. Everything matters, because I love my job and want to do it as best I can.”

She breaks off with a laugh: “I should probably lighten up a bit.”

In legendary whodunnit The Mousetrap, Strong plays curmudgeonly retiree Mrs Boyle.

“I like her a lot – she is in a very bad mood and lets everyone know about it,” she explains. “All that stomping about is fantastic. The director says she’s getting more and more terrifying as we go along.”

First performed in 1952, starring Richard Attenborough and his wife Sheila Sim, The Mousetrap went on to become the world’s longest running stage production with a record-breaking run of more than 27,500 performances in London so far.

Of all the many millions of people who have seen it, however, Strong was not one of them.

“I didn’t know what to expect when I settled down to read the script, but right away, I was hooked,” she says. “I think Agatha Christie writes really well for women. We are used to the old telly series and I think we tend to forget that the books can be much darker.”

The Mousetrap is back on the road following the success of the first ever UK tour in 2012 and as well as the current run in Edinburgh, which ends tonight, the play will visit Glasgow in October although Gwyneth is relinquishing the role before then.

“I miss my grandsons too much,” she sighs. “That’s why I only agreed to half the tour – I just couldn’t last any longer without them.”

Baxter and Bertie are twins, aged two years and three months, and the light of their grandparents’ lives.

“We spend a day with them and our bodies feel 10 years older but our minds feel 10 years younger,” she smiles. “I can’t wait to get back to them – and to sleeping in my own bed. Absolute luxury.”

Strong is looking forward to returning to Edinburgh, where she once performed at the Traverse during the Fringe.

“This will be a very different experience,” she says. “Edinburgh at festival time is like nothing else. I love the weirdness of it – the way you get up and do a show at 9.30 in the morning, it’s bizarre.”

Away from her stage and screen work, Strong is patron of Ovarian Cancer Action.

“I wanted to support a cause I knew something about,” she says. “My mother died of ovarian cancer and it was shocking, absolutely devastating. She was very active, always working. Ovarian cancer kills more women than all the other gynaecological cancers together but it doesn’t get the attention it deserves.”

Following the tour, Strong is looking forward to having a summer break. “After that, no idea,” she says, cheerfully. “I don’t really have a big plan. I’ve always quite liked it that way, and I enjoy both theatre and television.”

She pauses. “There are fewer roles on telly for women of my age. It is changing, thank goodness, but too slowly for my taste.”

Strong adds: “I just want to continue being a working actress, doing different things, not getting stuck in one or the other.

“That’s all I ever hoped for and I think I’ve just about pulled it off.”

The Mousetrap is at Edinburgh Playhouse tonight and Theatre Royal Glasgow from October 28 - November 2.