Andi Oliver hosts as the top three chefs from yesterday's fish and main course rounds cook for the judges. At stake is the chance to cook their dishes as part of a special festive feast for some of the nation's key workers.With a Christmas theme and some of the country's most talented and imaginative chefs taking part, opulent food is on the menu. For the fish course salmon and turbot take centre stage, with the ‘the King of the Sea' cooked in a giant antique copper pan. For mains, there's mouth-watering venison and a roast combining 12 different birds.With actor and comedian Kerry Godliman joining Matthew Fort and Oliver Peyton in the judging chamber, the chefs also have the challenge of creating vegetarian alternatives to their dishes. And all this against the clock!Also joining the judging panel is Professor Tim Spector OBE from Kings College London. His symptom tracking app used by more than 4 million people has revealed vital information about Covid-19, including loss of taste and smell as a symptom. He's also a successful author whose books explore the science behind the food we eat.