A small suburban town on the outskirts of South-East London. Sidcup residents argue that it is part of Kent, because it has a Kent postcode (DA14). There is, however, compelling evidence that it is part of London; Sidcup telephone numbers have the London (0208) area code & Sidcup is part of the London borough of Bexley.
Sidcup has a reputation of being a boring place inhabited by boring people. This has been exploited by advertisers; a 2000 VW Golf advert, which was challenging peoples stereotypes about cars, showed a man standing atop a mountain carying a sign which said "I live in Sidcup", the implication of which was that Sidcupians are perceived as not being the kind of people who climb mountains. In reality, Sidcup is no different from any other middle-class suburb of London. They're all boring, as a result of having a population of families and OAPs.
Sidcup is the inspiration for the very amusing Sidcup Massive website (http://www.ogmac.co.uk/sidcup/), which makes fun of large section of Sidcup's population, particularly all young people who are not exactly like the author. On the upside, this does mean making fun of boy racers. If you're not a resident of SE London, you won't get half the jokes.
No-one interesting has ever really come out of Sidcup. Until recently, it's claim to fame was having Sir Edward Heath, probably the worst ever Conservative Prime Minister, as its MP, but he retired at the last General election.