Sidcup was a parliamentary constituency centred on Sidcup, an outer suburb of London in the London Borough of Bexley. It returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom.
The constituency was created for the February 1974 general election, and abolished for the 1983 general election, when it was partially replaced by the Old Bexley and Sidcup constituency.
More information, including election results, on the Wikipedia page is [1]