TODAY’S RADIO

Natural Histories 11AM, RADIO 4 Bloodsucking leeches have blades on their jaws to slice their way through a host’s skin and get at the blood. Leeches were used for centuries in medicine, when blood-letting was seen as a cure. They are back in vogue among some of the medical profession, and are sometimes used after surgery. Leeches are also used in alternative therapy as a treatment for osteoarthritis. Brett Westwood looks at the strangeness of leeches in his continuing series on nature and human culture. The Curse Of Open Plan 4PM, RADIO 4 All this ‘knocking through’ and ‘opening up’ in offices and homes – to let in light and air – has forced workers and families to spend far too much time together. Julian Treasure looks at the noisy downside of open-plan design. Great Lives 4.30PM, RADIO 4 The businesswoman Hilary Devey, formerly of Dragons’ Den, joins Matthew Parris to sing the praises of fellow Lancashire lass Gracie Fields. Hilary, like Gracie, had a tough start in life and, like Gracie, lived above a fish-and-chip shop. Hilary tells the story of the singer’s life, with some grace notes from Sebastian Lassandro, the president of the Gracie Fields Appreciation Society. BBC Proms 2016 7.30PM, RADIO 3 Schubert wrote his mighty Ninth Symphony knowing that his days were numbered. The Austrian composer died before his 32nd birthday of the syphilis that threw such a terrible shadow over his short life. Despite this, the symphony, performed tonight by the BBC Philharmonic, is full of energy and life; it’s unlikely that Schubert ever heard it performed. Gilles Peterson’s Musica Brasileira 10PM, RADIO 2 Gilles Peterson scratches beneath the surface of South American pop to play some top-class yet lesser-known Brazilian music. Gilles picks a rare track from Jose Prates, punk rock from Sao Paulo, Brazilian soul, Amazonian dance and other off-the-beaten-track tracks, as a musical prelude to the 2016 Olympics. SJ

Gracie Fields (4.30pm, Radio 4)