Philomena Cunk, the breath-takingly dim-witted arts and history presenter, ought to do a series on classical music, when she's finished her moronic survey of our island race, in Cunk On Britain (BBC2). That might take some time, since she began with the Big Bang, in an account that promises to travel 'from ancient man to Ed Sheeran'.

Cunk, played with a face as cold and immobile as a side of mutton by Motherland actress Diane Morgan, is a send-up of every self-regarding TV personality who ever recited a script while standing on a windswept cliff-edge and gazing portentiously at the horizon.

'She's like an idiot twin sister,' says Morgan. 'Occasionally she'll get things so right you think maybe she isn't an idiot. Maybe she's a genius.'

The TV in-jokes wear a bit thin. But her malapropisms are hilarious: when she talks about the king of the dinosaurs, 'T'yrannical sawdust rex', or the 'Baywatch tapestry', she's in the great comic tradition of Joyce Grenfell and Dame Edna.

The professors and historians facing her pea-brained questions evidently knew what to expect, and played along. Ronald Hutton and Neil Oliver were trying not to giggle -- but full marks to the lady at the National Archives who talked to Cunk like a weary primary schoolteacher.

No, she explained patiently, the Domesday Book isn't cursed. Perhaps they're used to daft questions at the National Archives.

Preview - Cunk on Christmas

Following a previous episode where Cunk "examined" the life of Shakespeare, this time around she looks at everything to do with Christmas, from the birth of Jesus and the pagan origins to Santa Claus and "Sir Charles Dickings".