20 cheapest London postcodes revealed, with Thamesmead (SE28) the cheapest at £340,030, while W1S (Hanover Square) and SW1A (Whitehall)

20 cheapest postcodes in London revealed: Thamesmead (SE28) is the cheapest spot with an average home cost of £340,030, according to a study by Online Marketing Surgery and Cardinal Steels using HM Land Registry data. Other affordable areas include Barking (IG11), Dagenham (RM10), and Romford (RM1). The most expensive postcodes are W1S (Hanover Square) and SW1A (Whitehall) at £5.6m each.