Complex sentence: Sir Peter Lewis Gregson GCB (28 June 1936-12 December 2015) was a British civil servant, permanent secretary of the Department of Energy from 1985 to 1989, and of the Department of Trade and Industry from 1989 until his retirement in 1996.
Split into simpler sentences: Sir Peter Lewis Gregson, GCB (28 June 1936-12 December 2015) was a British civil servant. He was Permanent Secretary of the Department of Energy from 1985 to 1989, and of the Department of Trade and Industry from 1989 until his retirement in 1996.