Peter Graham Hewett, known as Graham Hewett, joined the Civil Service in 1969. In the Civil Service, he specialised in transport planning and undertook roles in the Department of Environment, New Towns Directorate, Nature Conservancy Council and National Bus Company. He moved on to be the British Rail sponsor in the Department for Transport.

In 1990, he joined the Network SouthEast sub-sector of British Rail as Director of Strategic Planning. He then became the Deputy Secretary of the British Railways Board from 1993.