The street was built in the 1680s by Sir George Downing, 1st Baronet, on the site of a mansion, Hampden House. Downing was a soldier and diplomat who served under Oliver Cromwell and King Charles II, and who invested in properties and acquired considerable wealth. In 1654, he purchased the lease on land east of Saint James’s Park, adjacent to the House at the Back, and within walking distance of parliament. Downing planned to build a row of townhouses “for persons of good quality to inhabit”. However, the Hampden family had a lease which prevented their construction for 30 years. When the Hampden lease expired, Downing received permission to build further west to take advantage of recent developments. The new warrant issued in 1682 reads: “Sir George Downing … [is authorised] to build new and more houses further westward on the grounds granted him by the patent of 1663/4 Feb. 23. The present grant is by reason that the said Cockpit or the greater part thereof is since demolished; but it is to be subject to the proviso that it be not built any nearer than 14 feet of the wall of the said Park at the West end thereof.”
12 Downing Street, formerly the Chief Whip’s Office, houses the Prime Minister’s Press Office, Strategic Communications Unit and Information and Research Unit. In the 1820s it was occupied by the Judge Advocate-General, although it remained in private ownership. It entered government hands when purchased by the East India Company in 1863, and was occupied by the marine and railway departments of the Board of Trade. It was originally numbered 13, but was partially re-built and re-numbered following the demolition of Number 14 in 1876. It was badly damaged by fire in 1879, and underwent further changes.
14 Downing Street formerly closed off the western end of the street. It was acquired by the Crown in 1798, and was used by the War Office and Colonial Office in the 19th century. Some parts were demolished in the 1860s, and by 1876 it had been removed completely.
15–16 Downing Street, long since demolished, formerly housed the Foreign Office, which also occupied two houses on the south side of the street.
18 Downing Street was occupied by the West India Department of the Colonial Office.
