The taller structure was required to protect the radio links' line of sight against tall buildings then planned in London.

Links were routed via GPO microwave stations Harrow Weald, Bagshot, Kelvedon Hatch and Fairseat, and locations including the London Air Traffic Control Centre.

[citation needed] The tower was designed by the Ministry of Public Building and Works, under chief architects Eric Bedford and G R Yeats.

Reginald Bennett MP asked the Minister of Public Buildings and Works, Geoffrey Rippon, how, when the crane on the top of the new Tower had fulfilled its purpose, he proposed to remove it.

The revolving restaurant was prefabricated by Ransomes & Rapier[10] and the lattice tower by Stewarts & Lloyds subsidiary Tubewrights.

[11] The tower was topped out on 15 July 1964, by Geoffrey Rippon[12] and inaugurated by Prime Minister Harold Wilson on 8 October 1965.

Above that was a 35-metre (115 ft) section for the microwave aerials, then six floors of suites, a revolving restaurant, kitchens, technical equipment, and finally a cantilevered steel lattice tower.

[16] The stainless steel clad windows were made by Henry Hope & Sons Ltd.[17] The tower was opened to the public on 19 May 1966, by Postmaster General, Anthony Wedgewood Benn and Billy Butlin,[18][19] with HM Queen Elizabeth II having visited on 17 May 1966.

Butlins' Top of the Tower revolving restaurant on the 34th floor made one revolution every 23 minutes[21][22] and meals cost about £4.

[25] A bomb exploded in the ceiling of the men's toilets at the Top of the Tower restaurant at 04:30 on 31 October 1971,[24] the blast damaged buildings and cars up to 400 yards (370 m) away.

[citation needed] The tower's microwave aerials remained in use into the 21st century, connected to subterranean optical fibre links.

It replaced an earlier light projection system and incorporated 529,750 LEDs arranged in 177 vertical strips around the tower.

[7][43][44] The tower has appeared in novels, films and on television, including Smashing Time, The Bourne Ultimatum, Space Patrol, Doctor Who, V for Vendetta, 28 Days Later, 28 Weeks Later, The Union and Danger Mouse.

[52] In May 1969, the tops of the GPO Tower and the Empire State Building in New York City served as the start and finish lines of the Daily Mail Trans-Atlantic Air Race.

The race between the two buildings was held over an eight-day period and commemorated the 50th Anniversary of the first non-stop transatlantic flight of Alcock and Brown.

[55] It is often said that the tower did not appear on Ordnance Survey maps, despite being a 177-metre (581 ft) tall structure in the middle of central London that had been open to the public.