BBC prepares to film two novels by the original 'It-Girl', Nancy Mitford

Two novels by Nancy Mitford which explore the social morals of the English upper classes are to be dramatised by the BBC later this year.

The costume drama, which is to be broadcast in autumn, will condense two linked novels by Mitford, the socialite for whom the phrase "It-Girl" was coined in the 1930s.

Mitford, the eldest of six aristocratic sisters, wrote the two novels being used by the BBC in the 1940s. The Pursuit of Love (1945) and Love in a Cold Climate (1949) were semi-autobiographical studies of the mores and behaviour of the English gentry. Although the BBC has yet to cast or fully cost the series, the decision to dramatise Nancy Mitford novels will unleash a wave of interest in her family's remarkable and at times notorious activities.

Filming on the series is due to start in June. The BBC said yesterday that it would be written by Deborah Moggach and co-produced by Kate Harwood, the partnership behind the recent mini-series starring Sheila Hancock and Keith Barron, Close Relations.

The six Mitford sisters were raised in Swinbrook, Gloucestershire, the daughters of Lord Redesdale. He was immortalised in Nancy Mitford's novels as the remarkably eccentric and ill-tempered Uncle Matthew.

They mixed with famous figures of the period such as Sir Winston Churchill and Evelyn Waugh. But it was her sisters' fascination with pre-war fascism which gave the family its notoriety.

Her sister Diana stirred up a controversy which continues today by leaving her first husband to marry Sir Oswald Mosley, founder of the British Union of Fascists. Unity became obsessed with Hitler, killing herself after Britain declared war on Germany.

Deborah married the Duke of Devonshire, while Jessica was the left-wing rebel of the family. She eloped with Esmond Romilly, who fought against Franco in the Spanish Civil War, and then emigrated to the United States, where she became involved in the trade union movement.

Nancy also lived abroad for much of the latter part of her life, moving to Paris, where she died of cancer in 1973.