Sir Edward Heath has announced his retirement from parliament at the next general election.

The pro-European Tory was prime minister from 1970 until 1974 and, as the longest serving MP of more than half a century, is the father of the house. It was in this role that he presided over the controversial election of the new speaker on Monday.

Sir Edward's term as prime minister was during a period marked by industrial unrest and an economic crisis that led to him introducing the three-day week. His battles with the unions later became a focal point for Margaret Thatcher and her governments. Sir Edward never forgave her for ousting him as Tory leader after he lost the 1974 election.

The 84-year-old announced his decision in a letter to his constituency association of Old Bexley and Sidcup. He said: "I am immensely proud of having been returned by the electorate of Bexley at every general election since February 23, 1950, a period of more than 50 years."

Tony Blair paid tribute, saying: "Sir Edward has made an outstanding contribution to British political life, both through his service as an MP and as prime minister."

Conservative leader William Hague said: "Ted Heath's retirement from the House of Commons at the next election will leave a gap that no-one can fill."

His majority at the last election was 3,569. Heath will be succeeded as father of the house by Labour MP Tam Dalyell.