The early laboratory had several specialist divisions: Chemistry (initially headed by Egon Bretscher, later by Robert Spence), General Physics (H.W.B. Skinner), Nuclear Physics (initially headed by Otto Frisch, later E. Bretscher), Reactor Physics (John Dunworth), Theoretical Physics (Klaus Fuchs, later Brian Flowers), Isotopes (Henry Seligmann) and Engineering (Harold Tongue, later Robert Jackson). Directors after Cockcroft included Basil Schonland, Arthur Vick and Walter Marshall.
A successor to GLEEP, called BEPO (British Experimental Pile 0) was constructed based on the experience with GLEEP, and commenced operation in 1948. BEPO was shut down in 1968.
LIDO was an enriched uranium thermal swimming pool reactor which operated from 1956 to 1972 and was mainly used for shielding and nuclear physics experiments. It was fully dismantled and returned to a green field site in 1995.
A pair of larger 26 MW reactors, DIDO and PLUTO, which used enriched uranium with a heavy water moderator came online in 1956 and 1957 respectively. These small reactors were used primarily for testing the behaviour of different materials under intense neutron irradiation to help decide what materials to build reactor components out of. A sample could be irradiated for a few months to simulate the radiation dose which it would receive over the lifetime of a power reactor. They also took over commercial isotope production from BEPO after that was shut down. DIDO and GLEEP themselves were shut down in 1990 and the fuel, moderator and ancillary buildings removed. The GLEEP reactor and the hangar it was situated in were decommissioned 2005. The current plans are to decommission the BEPO, DIDO and PLUTO reactors by 2020.
During the 1980s the slowdown of the British nuclear energy program resulted in a greatly reduced demand for the kind of work being done by the UKAEA. Pressures on government spending also reduced the funding available. Reluctant to merely disband a quality scientific research organisation, UKAEA was required to divert its research effort to the solving of scientific problems for industry by providing paid consultancy or services. UKAEA was ordered to operate on a Trading Fund basis, i.e. to account for itself financially as though it was a private corporation, while remaining fully government owned. After several years of transition, UKAEA was divided in the early 1990s. UKAEA retained ownership of all land and infrastructure and of all nuclear facilities, and of businesses directly related to nuclear power. The remainder was privatised as AEA Technology and floated on the London Stock Exchange. Harwell Laboratory contained elements of both organisations, though the land and infrastructure was owned by UKAEA.
The name Atomic Energy Research Establishment was dropped at the same time, and the site became known as the Harwell International Business Centre. The adjacent site known as Chilton/Harwell Science Campus houses the Rutherford Appleton Laboratory, ISIS neutron source and Diamond Light Source. In 2007, both sites started to use the name Harwell Science and Innovation Campus.