Mullard Radio Astronomy Observatory (MRAO) is home to a number of large aperture radio telescopes, including the One-Mile Telescope, 5-km Ryle Telescope, and the Arcminute Microkelvin Imager.
Radio interferometry started in the mid-1940s on the outskirts of Cambridge, but with funding from the Science Research Council and a donation of £100,000 from Mullard Limited, construction of the Mullard Radio Astronomy Observatory commenced at Lord’s Bridge, a few kilometres to the west of Cambridge. The observatory was founded under Martin Ryle of the Radio-Astronomy Group of the Cavendish Laboratory, University of Cambridge and was opened by Sir Edward Victor Appleton on 25 July 1957. This group is now known as the Cavendish Astrophysics Group.

The site is located at Lord’s Bridge, Cambridgeshire on a former ordnance storage facility, next to the now-abandoned Cambridge-Bedford railway line. A portion of the track bed of the old line, running nearly East-West for several miles, was used to form the main part of the “5km” radio-telescope and the Cambridge Low Frequency Synthesis Telescope.