David Dimbleby introduces coverage of tonight's by-elections in Winchester and Beckenham.
The Liberal Democrats took Winchester from the Conservatives by just two votes at the general election, but a re-run has been ordered by an electoral court after 55 votes were found to be unfranked.
Meanwhile the Conservatives will be hoping to hold the London seat of Beckenham following the resignation of MP Piers Merchant.
Followed by Weather