WHILE the new series of Seventies hit Upstairs Downstairs introduces many new faces, there is one very special one from the past. Jean Marsh, who co-created the series with fellow actor Eileen Atkins, returns to the role of housemaid Rose.

During the past 35 years, many fans have asked for a remake, and many writers and producers offered to do it, but the answer has always been no.

But when Cranford writer Heidi Thomas and a BBC producer approached her, Marsh finally had a change of heart.

“I said yes, partly because it was the BBC, because it’s so chic, and partly because of timing,” she says. “I realised if we didn’t do something now, I might not be alive if it was done again. Enough time has gone by that it won’t offend people to recreate it. People aren’t necessarily going to say, ‘How could you do that Jean?’”

The glossy three-part series picks up in 1936 when new owners Sir Hallam Holland (Ed Stoppard) and his wife Lady Agnes (Keeley Hawes) make a fresh start in the iconic town house.

Viewers will see Rose wandering through the mess that the town house in Belgravia’s Eaton Place has become after six years of standing derelict. It’s an emotional moment for Rose and Marsh: “I can’t think about coming back without feeling tearful, not bad tearful, but just emotional.

The past is there, exquisitely recreated, and it’s startlingly upsetting to see the house where I lived for five years, and was Rose for 35 years, looking a mess,” Marsh says.

She urges viewers to gloss over the fact that in real time, Marsh is 25 years older, but for her character, only six have passed. She points out she “didn’t age in the original series”. “We just jogged along and somehow 25 years passed,” she says.

As the only original cast member to return, 76-year-old Marsh is excited that now-Dame Eileen Atkins will this time be involved. Her old friend couldn’t take on a role in the original series because she had theatre commitments. But even after the 35-year gap, they still won’t get to work together, as Atkins has been cast as one of the “‘upstairs”

folk, playing Lord Hallam’s eccentric mother.

As newly-promoted housekeeper, it’s Rose’s job to maintain the smooth running and harmony of the house. Her work’s cut out, as not only is there the inevitable bickering and jealousy among the servants, but Maud and her son have 30 years of family politics to sift through, Lady Agnes becomes obsessed with having a child, and the arrival of Agnes’s impressionable younger sister Persie (Claire Foy) causes unforeseeable trouble.

The tension is underpinned by events outside the house, with the popularity of the Fascist right in Europe coming to a head during the Cable Street Riots.

“The history is very important, and it’s told from the point of view of everybody who lives in the house,” says Marsh. “You couldn’t ignore history, otherwise it would be like the Archers, you know, when they’re having a nice cup of tea and worrying about a ewe stubbing its toe.”

She thinks it’s the preoccupation with class, even in our supposedly classless society, which makes dramas such as Upstairs, Downstairs and ITV1’s recent hit Downton Abbey so popular.

“It’s the contrast which is interesting.

There have always been ‘haves and have-nots’ and there’s still a class system in place. “There’s one on this series right now. When actors are in a series filming, they get given numbers. With us, one, two, three and four are all upstairs people, and downstairs starts with me.

That’s Upstairs Downstairs, it starts here – they automatically got the best billing.”

■ Upstairs, Downstairs starts on BBC1 on Boxing Day at 9pm.