Category: Semi-marginal Conservative seat

Geography: Eastern, Hertfordshire. The whole of the Watford council area and part of the Three Rivers council area.

Main population centres: Watford, Abbots Langley.

Profile: Covers the borough of Watford and some of the commuter villages around it, including Abbots Langley and Langleybury. It is part of the London commuter belt, but is also an economic centre in its own right, housing the headquaters of several major companies such as JD Wetherspoon, Mothercare and Camelot.

Politics: Historically this was a classic Labour vs Conservative marginal, regularly swapping between the parties with the ebb and flow of party popularity. It was won by Labour in the 1997 landslide, with Claire Ward becoming the second youngest MP at the age of 24. Since then the Liberal Democrats have made strong advances in the seat, narrowly taking second place from the Conservatives in 2005 and making this a tight three way marginal by the time of the 2010 election. The Conservative victory here was in the face of a double handicap - not only did they start in third place behind the Liberal Democrats, but their original candidate for the election, Ian Oakley, was forced to stand down in 2008, and was later convicted of criminal damage and harrassing his Lib Dem opponent. Richard Harrington eventually won anyway, with a small majority over the Liberal Democrats in second. The collapse of the Liberal Democrats in 2015 left him with a far safer majority.