'The Great British Bake Off' bosses have made this year's set "almost impossible to breach".
The hit Channel 4 baking competition is to return for another helping later this year, and after creating a COVID-safe "biosphere" for contestants, crew and stars - including judges Paul Hollywood and Prue Leith, and co-hosts Matt Lucas and Noel Fielding - at the Down Hall Hotel in Hertfordshire, the producers are keen to ensure filming won't be "held up or cancelled".
A source told The Sun newspaper's Bizarre TV column: "The last thing the producers want is anything that could risk filming being held up or cancelled completely.
“So they’re not taking any chances when it comes to protecting the show, even arranging all the tents, huts and other temporary structures to help create a perimeter that is almost impossible to breach.
“If a spanner was thrown in the works it would be particularly galling for Channel 4 as 'Bake Off' is their most watched show."
As well as the main show, 'Bake Off' bosses are aiming to film various special episodes and 'Junior Bake Off' "in one batch" at Down Hall.
The insider added: "As well as filming the main show at Down Hall, they also make the Christmas Special, the celebrity specials and 'Junior Bake Off' in one batch.
"So there’s a lot at stake, and the message is: Please keep away or face being turned away.”
Matt, who co-hosts the show alongside Noel, previously revealed everyone working on the programme will bubble up to enable them to get around coronavirus pandemic restrictions - after the show created a "self-contained biosphere" between the cast and crew last year to ensure shooting could go ahead.
Bubbling up ahead of filming series 12 will also allow judges Prue and Paul to taste the contestants' creations, and Paul will be able to dish out his famous Hollywood Handshakes.
Matt said: "We're starting very soon. And like last year, we're going into a bubble.
"We are all self-isolating and getting tested, and then we're going into a COVID-free bubble so we can all taste each other's bakes and there can be handshakes, and all sorts.
"I've seen video clips of all the new bakers, and there are some brilliant ones in there."