Lies and Loyalties, By Rachel Billington

Rachel Billington is well versed in the politics and pain of large families who live in the public eye. Daughter of the Labour minister and prison reformer, Lord Longford, and his acclaimed historian wife, Elizabeth, sister of fellow-writers Antonia Fraser and Thomas Pakenham, cousin of Harriet Harman, she knows from the inside the dynamics of competitive and complex clans. So it is hard not to detect a whiff of autobiography from her latest novel. Lies and Loyalties chronicles the long-standing tensions of the five high-achieving but divided Barr siblings, and how they are exposed when one is apparently found dead.

Charlie Potts – he has changed his surname from Barr to his wife's after marrying a drug-addicted prostitute in a sincere but ramshackle effort to save her – suffers from mental illness. He has, his brothers are told, been found hanging from a tree in the grounds of a secure hospital. An inveterate campaigner, successfully so when he is well, Charlie appears to have got too close to a big political scandal.

The oldest Barr brother, Roland, barrister and pillar of the establishment (right down to secret liaisons with rent boys), would prefer the messy business to be swept under the carpet. In the other camp is his MP middle brother, Leo, in love with Roland's homely wife, Maggie. He takes up Charlie's crusade, asks pointed questions in Parliament, and risks disgrace by condemning his own government. His opposing loyalties – to party and family – are just one of the conflicts at the core of the novel.

Part thriller, part literary novel of ideas, Lies and Loyalties carries another echo of Billington's experience. Her own lawyer brother, Paddy, suffered in his lifetime from episodes of mental illness that cut short a glittering career at the Bar. But it is arguably the gift of the experienced novelist (this is Billington's 19th book) to take the germ of an idea from their own lives, but then let their imaginations soar.

Lies and Loyalties certainly does take wing. It is a complex human drama that also embraces questions not only of how we treat the mentally ill, but crime and punishment, the place of religion (another brother, Bill, is a Catholic priest), and the purpose of parliamentary democracy. What drives the novel forward and holds the narrative together is Billington's persuasive and intriguing portrait of a family whose members define themselves, first and foremost, in relation to their siblings.