<P> When the movement for Irish independence became increasingly violent, it was decided to retain the barriers, which were raised and strengthened . On 26 November 1920 construction commenced on a wooden barricade, 8 feet (2.4 m) high at the end of the street . They were described as being of a "substantial character" mounted on proper foundations and incorporated vehicle gates . The barriers were taken down in 1922 when the Irish Free State was created . </P> <P> Vehicle access was curtailed in 1973 when metal barriers were placed across the entrance to the street . In 1974, the Metropolitan Police proposed erecting a semi-permanent barrier between the pavement and carriageway on the Foreign Office side to keep pedestrians off the main part of the street . The proposal came with assurances that tourists would still be permitted to take photographs at the door of Number 10 . The Prime Minister, Harold Wilson, rejected the proposal, feeling that it would appear to be an unacceptable restriction of the freedom of the public . Wilson's private secretary wrote "I much regret this further erosion of the Englishman's right to wander at will in Downing Street ." </P> <P> In 1982 access was further restricted by railings and a demountable gate . They were replaced by black steel gates in 1989 . The increase in security was due to an increase in violence, particularly by the IRA during The Troubles . The Thatcher ministry was particularly moved to increase security after the 1979 assassination of Lord Mountbatten . </P> <P> The public right of way along Downing Street has not been extinguished nor subject to a gating order and the road retains the status of a public highway maintained by Westminster City Council . Public access was curtailed by relying on common law powers to prevent breach of the peace (although its legality has been questioned by a correspondent for New Statesman magazine). In 2005 Westminster City Council used anti-terrorism powers contained in the Civil Contingencies Act 2004 to formalise the restrictions by means of a traffic management order . </P>

When did they put gates on downing street