Leading international physicist, Sir William 'Bill' Mitchell, has died at the age of 77.

Mr Mitchell left Devon in 1943 to study physics at Sheffield and, after a spell with Metropolitan Vickers, was seconded to Bristol University, where he completed his PhD.

It was at Reading University in 1951 that his interest in optics -- particularly in light scattered by diamonds -- led him to establish a solid state physics group exploring the electronic properties of exotic materials.

He became deputy vice-chancellor at Reading before moving to Oxford University in 1978 to head the Clarendon Laboratory.

While at Oxford, he carried out pioneering work using the Dido and Pluto test reactors at Harwell Laboratory.

He chaired the Science and Engineering Research Council's neutron beam research committee from 1966-74, and was the driving force behind the UK's investment in the high-flux beam reactor at the Institut Laue-Langevin in Grenoble.

He became the chairman of SERC, which includes the Rutherford Appleton Laboratory, Chilton, in 1985.

In the role, he inherited a row over moving the Royal Greenwich Observatory from Herstmonceux, Sussex, to Cambridge.

In 1991, he served as president of CERN, the European particle physics research centre in Geneva.

He was a Fellow of the Royal Society and the Royal Society of South Africa.