TODAY’S RADIO

The Forum

10.06AM, 12.06AM, BBC WORLD SERVICE ★★★

Bubonic plague swept through Hong Kong in 1894 as a young Swiss doctor, Alexandre Yersin, arrived in the city to investigate causes of the disease. The British authorities refused to help him, so Yersin set up a makeshift laboratory in a straw hut. Bridget Kendall tells the story of the man who identified the bacterium behind the disease that, over the centuries, had condemned millions of people to a dreadful death.

Afternoon Concert

2PM, RADIO 3 ★★★★

Casta Diva is one of the most famous arias in 19th-century opera, and is a plea to the chaste goddess of the moon to bring the peace she created in the heavens to Earth. It is a beautiful work,

Marina Rebeka (2pm, Radio 3) and will be sung by the soprano Marina Rebeka in this production of Bellini’s two-act tragedy Norma.

The Classic FM Concert

8PM, CLASSIC FM ★★★

So much of Ralph Vaughan Williams’s music evokes images of lush, green English countryside. John Suchet includes Vaughan Williams’s setting of Linden Lea, a work by a Dorset poet, in this concert of the great British composer’s music. The English Folk Song Suite and The Lark Ascending are also on the bill.

The Untold

8.30PM, RADIO 4 ★★★★

Phil and his son, Jordan, are the leaders of a group called Predator Exposure. Posing online as children or teenagers, they set traps to lure in possible child abusers. Members of the group were taken to court over their actions against suspected paedophiles. They were found not guilty, and vowed to continue their work tracking down suspects. Rob Lawrie meets members of Predator Exposure, and hears about their tactics and motivation.