LB Greenwich
Greenwich (SE10)
Royal Observatory (south side of Meridian Building)
Distance (S) from Greenwich
OS map detailsOS Explorer: 162 or 162
OS grid refTQ 38883.77315
WGS84 lat/long51.477752, -0.001505
TypeGround (line) | Wall (line) | Sign on post(s) | Plaque (wall)
Marking datec. 1967 & later
AccessRestricted (charged entry)
Greenwich Meridian Marker; England; LB Greenwich; Greenwich (SE10)


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The following résumé of the history of this marking is subject to change, and should be regarded as work in progress rather than definitive.

1967: Opening of Meridian Building to the public for the first time following extensive refurbishment. Marking of Line for the first time with a brass strip in a stone slip set into a gravel path, continuing vertically up the retaining wall (southern boundary) to match that in courtyard. There is a possibility that it was located a few inches too far west (this is still being investigated). Sign on vertical shutter of Airy Transit Circle (ATC) carrying the words: PRIME MERIDIAN OF THE WORLD | WEST LONGITUDE | EAST LONGITUDE | Centre of transit circle | Latitude 51º28’38”.2 north | Longitude 0º00’00”, probably erected at this time. Shutters painted blue. There also appears to have been another sign with similar or identical wording beneath the shutter that was only revealed when the shutter was open. The sign(s) may have been replaced from time to time (dates not yet ascertained) with the latitude given (on at least some) as 51º28’38” rather than 51º28’38”.2 and with a very slightly different layout of the wording.

1984, June 26: Trees planted on lawn on either side of the (unmarked) Line by HRH Prince Philip and Arnold Wolfendale the Astronomer Royal as part of the ‘centenary’ celebrations for the Prime Meridian. Missing by 1992 if not earlier.

Late 1980s: Around this time, (possibly slightly later), the Line was extended northwards across the lawn towards the building with a line of additional paving on either side.

c.1990: Time zone map erected on railings (a second was erected in the Courtyard on the other side of the building). New sign on vertical shutter of ATC, with changed wording: Longitude Zero | The Prime Meridian | of the World | Greenwich | Latitude 51º28’38” | Longitude 0º0’0” | East Longitude | West Longitude. Even though this sign faced south, it appears to be an exact duplicate of the sign erected at the same time on the opposite side of the building that faced the other way. This resulted in the East Longitude and West Longitude markings being the wrong way round.

1992: Following closure of Line in courtyard in late 1992 for remodelling, this became the Line on which visitors to the Observatory took their photographs. Blue hording erected across line in front of building as a backdrop, carrying the words: LONGITUDE ZERO | THE PRIME MERIDIAN | OF THE WORLD | GREENWICH| WEST | EAST , along with an image of a symbolic globe with the Meridian marked and the words ‘0º00’00” Longitude’.

1993: Line shortened back to original 1967 length (or thereabouts). Grass adjacent building reinstated. ATC Shutters painted black with red line to depict Meridian. New stainless steel sign with revised wording on shutter of ATC, to match style of new sign on the other side of the building. The revised wording was as follows: Prime | Meridian | of the | World | West East. Replacement of rotten lower shutter by 2004, but with red line omitted.

2006, Nov: Remaining red vertical line on upper shutters depicting Meridian, removed during redecoration.

2007: Trial of present entry route for visitors into the Observatory. Removal of time zone map and signs both on and adjacent to ATC shutter to make the presence of the Meridian less obvious, in order to ease visitor flow.

2009: New ramped path built over northern end of brass line. Line marked in new path adjacent to the building with granite setts (but an inch or so too far to the west). Removal of paving and remainder of stone slip on the ground (but not the strip itself, which remains under a planting of shrubs). Later removal of wall slip prior to rebuilding of retaining wall (not subsequently reinstated – most probably skipped).

Image: 22 June 1992, showing back to front sign
Image: late 1992, showing blue hording erected as backdrop during refurbishment
Royal Observatory, Greenwich (part of the National Maritime Museum)