It may may now be tucked away behind trees next to the M271, but their former offices were a Hampshire landmark.

The Queen officially opened the Ordnance Survey’s headquarters in Maybush, Southampton which had taken more than five years to build and bring into operation.

The opening of the buildings on May 1, 1969, ironically meant more work for the company as they had to redraw maps to include their headquarters on the 23-acre site.

The ordnance survey can trace its links with Hampshire back to 1841, following a fire that destroyed its previous base in the Tower of London.

It was purely by chance that Southampton became the mapmakers new home as the Hampshire town happened to have empty barracks which could be utilised.

It was suggested by the government a few years later that the map office should move back to London “thereby saving the constant journeys which take place to and from Southampton, and a good deal of postage”.

Before the Ordnance Survey moved into The Avenue building, it already had an interesting history. They started life as a cavalry barracks before being taken over by by the Duke of York’s Royal Military School, then called the Royal Military Asylum, lending its name to the nearby Asylum Green.

Another fire struck in December 1940, this time caused by Luftwaffe bombs, seriously damaging the offices and resulting in the loss of many valuable records and instruments.

Once the Second World War was over, the Ordnance Survey was housed in numerous temporary buildings in and around Southampton, so with the opening of the site in Maybush, was brought together under one roof.

The Queen had a particularly busy day on May 1, 1969, as before she arrived at OS with Prince Philip, the royal couple had toured Cunard’s new liner Queen Elizabeth 2. It was the day before the ship departed on her first transatlantic crossing.

The royal visit made history that day as it was the first to be made to the OS by a reigning monarch.

“Thousands of cheering employees, their families and friends greeted the Queen and Prince Philip when they arrived at the new Ordnance Survey headquarters in Maybush,” read the Daily Echo at the time.

The Queen unveiled a plaque after congratulating the Ministry of Public Building and Works, which designed and managed the project.

“No important development can take place , either in town or country without reference to an accurate and up-to-date map or plan,” the Queen told the crowds.

Many important operations were conducted on the premises through the years, including the calculations for the digging of the the Channel Tunnel.

The site became synonymous with Maybush over the 40 years it was there, up until the points when Prince Philip opened their new building in Adanac Park on October 4, 2011.

The former Maybush site is now occupied by homes and shops.