Dame Mary Berry is a baking superstar – one of the nation’s most-loved cookery writers and TV personalities. She is also over 80 (she turns 86 in March), putting her in one of the categories deemed most vulnerable to coronavirus.

And so, as well as the usual social distancing guidelines and regular testing, extra precautions were taken to keep Bath-born Berry safe on the set of her latest TV series, BBC One’s Celebrity Best Home Cook.

Firstly, a 15ft-high special viewing platform was built as a mezzanine floor for her, so she could look down on everyone (“It was a bit royal!” she says, when I suggest she must have felt like the Queen). She was also given special opera glasses to make sure she could see everything the cooks were doing down below as they prepared their various dishes, hoping to impress Berry and her fellow judges, Angela Hartnett and Chris Bavin.

“I could see exactly what was going on – and then suddenly, I would want to talk to people, so I could blow a whistle or shout and they’d immediately stand to attention and tell me what they were up to,” recalls the former Great British Bake Off presenter, who recently told the Radio Times that she and her husband Paul, 88, have now had the Covid-19 vaccine. “It was different, but it certainly worked.”

Meanwhile, witty host Claudia Winkleman says her dressing room was “taken over by the Covid medical staff, who were absolutely amazing”. “So, I literally got changed in the corridor,” quips the London-born star, 49, adding with a chuckle. “That was fine – Mary’s seen worse.”

Winkleman is immensely likeable; her self-deprecating humour puts you at ease and you can tell she’d be a reassuring presence for the Celebrity Best Home Cook contestants. But if something went wrong with any of their recipes, she “couldn’t get in there and give them a squeeze, or help them stir something”, as she did on the previous two series of Best Home Cook.

“I can’t cook but I would do whatever I could to help them – but this time I couldn’t get away with anything. A) I wasn’t allowed to go close to them and B) Mary, Angela and Chris didn’t miss a thing because they were up there [on the mezzanine].”

There were lots of scenes where she and the judges would talk like they normally would, she recalls, but they had to be three metres apart, “so it looked like we were creating Eighties album covers.” “So, we named ourselves Mary and the Social Distancers because we were so far away from each other,” continues the charismatic Strictly Come Dancing host. “But there was still the same camaraderie, the same laughs, the same sparks. It was brilliant.”

She adds lovingly: “I was worried because I’m so used to standing right next to Mary; I mean, we held hands through most of series one and series two! But it really worked!”

Ten stars from the worlds of sport, TV and comedy will be cooking their hearts out in Celebrity Best Home Cook in a bid to be crowned winner at the end of the eight-part series. Each episode consists of three rounds: The Ultimate, set by Berry; The Rustle Up, set by Bavin; and The Eliminator, set by Hartnett. And amiable, chatty Berry admits she was nervous about it being celebrities in the kitchen this time. “I thought, ‘It’s not going to be the same, they won’t take it seriously, and they won’t have skills’. And I was so surprised! It was far, far better than I had thought – in fact, I loved it.”

What does she think is the most common mistake people make with their home cooking? “Well, I think definitely not sitting down and doing a bit of planning. I mean, I’m making a fish pie today, and I shall make two. One I will put in the freezer for perhaps early next week, and one we’ll have tonight.”

This leads to a discussion about the pair’s favourite comfort food, something we can all agree we need as the Covid-19 lockdown continues. “I like anything with mashed potato on the top,” enthuses Winkleman. “Like when Mary said fish pie… I mean, if we weren’t in lockdown, I’d get in the car over to Mary’s right now and say, ‘Hello Paul, just me! Budge up’.

“I’m going to try, for the first time ever in my life, to make a chickpea curry today. I’ve discussed it for about seven days – the kids can’t bear me. But I like one-pot cooking.”

The public loves watching TV shows about cooking, and Berry suggests one reason is the fact “people can relate to it”. “I mean, gone are the days when it was just mum who’s doing the cooking; everybody’s taking part. All through lockdown children have been baking like mad, cooking perhaps one course. The chaps are cooking as well.

“I think it’s something that everybody has a go at and really finds that it’s very rewarding, particularly for children who perhaps haven’t done well at school and are finding all this homeschooling really difficult.”

On the topic of homeschooling, mother-of-three Winkleman confides she’s “not very good at it”. “The main two words that I use are, ‘Ask Dad’, because there are whole sections of maths I have absolutely no idea about. But I’m lucky, two of mine are quite big.

“I think it’s much harder if you have really little ones, or six-year-olds or seven-year-olds, but my youngest is nine and the schools are being brilliant. I mean we’ve always known that teachers are extraordinary, but this has shown us just how amazing they are.”

Celebrity Best Home Cook will air every Tuesday and Wednesday on BBC One for eight episodes from January 26 and online via the BBC iPlayer.