It is the final farewell to Gleep, Europe's first nuclear reactor at Harwell.

Gleep - Graphite Low Energy Experimental Pile - is now in the final stages of being decommissioned by the Atomic Energy Authority.

It is 57 years since it went critical in 1947 and was a triumph for British scientists pioneering nuclear technology in the UK, providing them the first opportunity to test how a nuclear reactor worked.

Gleep was still in operation as a test reactor until 1990 when it was shut down.

Generally operating at 3kW, Gleep was used for initial investigations into how to make nuclear energy work and was a forerunner of Britain's nuclear power station programme.

It was later used as an international standard for materials testing and calibration.

Harwell spokesman Nick Hance said decommissioning has taken some 14 years partly to allow the low level radioactivity to decay and also because it was housed in a 70-year-old wartime aircraft hangar where other research work was still being carried out.

Initially one of the key challenges in decommissioning the reactor was the removal of 11,500 spent fuel rods. Gleep had been refuelled only once, in 1960, and so experience of fuelling and defuelling was limited.

In order to defuel the reactor, a specialist remotely-operated crane was designed and commissioned.

Mr Hance said: "Following the final removal of the concrete and steel outer shell of the reactor, this part of the 250-acre Harwell Business Centre will be delicensed as a nuclear site and the hanger will be demolished."

Along with other nearby buildings which are being cleared, it will allow more of the Harwell site to be redeveloped.