When all government powers were held by one person (Kings - who made the law; carried it out; and personally judged in disputes) - the developing institutions sat where he was. If the King was in Oxford, Parliament met at Oxford.
With time the powers drained from the King to the institutions themselves. They gained permanent places to meet - so today we have the Houses of Parliament; the Supreme Court Building (formerly known as Middlesex Guildhall); the Royal Courts of Justice - and 10 Downing Street.
For most of the 20th Century Cabinet meetings were held in no 10, but recently the Cabinet has "played away from home." A recent House of Commons Library paper lists these meetings.
It can be accessed here.
