Dartford (UK Parliament constituency)

Dartford
County constituency for the House of Commons
Boundary of Dartford in Kent.
Location of Kent within England.
County	Kent
Electorate	74,756 (December 2010)
Major settlements	Dartford
Current constituency
Created	1885
Member of parliament	Gareth Johnson (Conservative)
Number of members	One
Created from	West Kent
Overlaps
European Parliament constituency	South East England

Dartford is a constituency represented in the House of Commons of the UK Parliament since 2010 by Gareth Johnson of the Conservative Party. The constituency is currently the longest serving 'bellwether' constituency in the UK Parliament as the party of the winning candidate has gone on to form the government in every General Election since 1964.

The seat was created under the Redistribution of Seats Act 1885. This Act added a net 18 seats, but its main purpose was to correct the over-representation of minor, often still old boroughs and depopulated county divisions. In their place were created new seats with a larger population. In Kent the Act finally abolished the Sandwich constituency, which sent two MPs until 1885. It also halved the representation of no fewer than four other historic towns. In contrast a seat for Dartford, the North-Western Division of Kent or North West Kent, was created.

In the early 20th century, the Dartford constituency was very much a bellwether: Dartford's results later shifted towards the left: in 1938 and then in 1951 (as well as the two intervening general elections) a Labour MP was elected, on those two occasions in opposition.

This was the first seat contested by Margaret Thatcher (then Margaret Roberts), at the 1950 and 1951 general elections. From 1945 until 2010, Dartford has been a Labour-Conservative marginal seat and thus a "bellwether" again: since 1964 the party winning the seat has gone on to form the government.