EVEN before The Queen became Britain’s longest-serving monarch last week she was probably the most photographed and filmed woman in the world.

This is a double-edged sword for anyone tasked with portraying Elizabeth II on stage – it means there’s plenty of source material to choose from, but every audience member has a good idea of what they think she’s like.

“They were also a bit solemn – if that’s the right word. Perhaps dignified would be better. I’d also been looking at film of The Queen dancing or playing with her dogs and I was interested in these moments of The Queen having fun.”

Susie, who is best known to TV audiences as the snooty BBC announcer from Victoria Wood – As Seen on TV, has also been taking some vocal coaching in order to give an accurate rendition of those very familiar tones. “We discovered that a slightly nasal voice is quite a good amplifier,” she adds.

Handbagged takes a comic look at the relationship between the two women, born only six months apart, who shared a sometimes uneasy relationship, exemplified by the weekly audience which all British monarchs and their Premiers are compelled to observe.

“Of course, nobody knows what happened on those occasions: not even a footman is allowed into the room where they meet,” explains Susie.

“I think that in the early days of the Thatcher premiership, The Queen may have hoped that Mrs Thatcher might become a confidante and that they would share informal conversations. But in practice Margaret Thatcher had no small talk. She had a single-track mind which left no scope for any chit-chat. The Queen is very good at using small talk in order to put people at their ease.”

As she approaches this most difficult role, it’s tempting to wonder if The Queen has ever slipped into a West End theatre, incognito, to see herself represented on stage. But Susie has her doubts.

“I don’t think she’d be especially interested in going to the theatre to see plays about herself and I’m sure that one of her staff would report back if there was anything untoward,” she states.

“She much prefers time spent at Balmoral and with her horses and dogs. She knows herself and she is not worried about how she is perceived which is why she was mystified by the whole Diana business.”

Discussion about the Royal Family can provoke mixed reactions. Susie, the grandchild of Muffin the Mule co-star Annette Mills, finds herself occupying the middle ground between royalist and republican.

“I think that the family should be smaller because all those stately homes must be expensive,” she muses. “I could live with a smaller family with no more than two palaces and the rest of them could go pedalling their bikes in the way the Dutch and the Scandinavian royals do.

“At the same time, the country would be a sadder place without the odd carriage and I’d rather the army was protecting The Queen rather than waging war somewhere.

“She’s apparently more popular than Queen Victoria, she doesn’t put peoples’ backs up and she’s comfortable as the mother of the nation… and the Royal Family make good theatre, after all.”

Handbagged starring Susie Blake as The Queen and Kate Fahey as Mrs Thatcher comes to Guildford’s Yvonne Arnaud Theatre from Monday (September 21) until Saturday, September 26.