In Our Time Radio 4, 9am & 9.30pm

Before the age of dinosaurs, the Earth was ruled by ancestors of the crocodile, including species that were the size of a bus or could run on two legs. Melvyn Bragg (right) begins a new series by looking at the reptiles' evolution.

In Ramblings (Radio 4, 3pm), Clare Balding explores the most westerly part of the British mainland as she walks along the coastline of the Ardnamurchan peninsula with

Dee Heddon, a professor of theatre at the University of Glasgow.

The Afternoon Concert (Radio 3, 2pm) features the Bavarian Radio Symphony Orchestra's performance of Schumann's Fourth Symphony.