The street and area known as Whitehall, where Whitehall Palace once stood, is now lined with government offices. The small, narrow Downing Street, which leads off from Whitehall, is probably the most securely guarded street in the whole of the United Kingdom, closed off to the general public. The reason is that the town house at No.10 is the official home and office of the British Prime Minister. The famous black front door, which appears to be made of wood, is actually blast-proof steel. Stand by the security gates and you’ll see a continuous succession of ministers, officials and other visitors being checked in and out by heavily-armed police.

Downing Street dates from the 1680s, when it was laid out by Sir George Downing. Back then it consisted of 20 houses but only four remain, joined into a complex of government offices, of which No.11 is the official home and office of the Chancellor of the Exchequer (the finance minister). No.10 took on its current role in 1735 when it was occupied by Sir Robert Walpole, First Lord of the Treasury, and effectively the first Prime Minister.