Subsequently he moved to Wiltshire as a director of a development company and promoted the continuing expansion of Swindon. This involved three major planning inquiries and culminated in what are now the Western and Northern expansion areas of the town where planning permission has been obtained for some 870 hectares of development. The northern expansion area alone involved fourteen landowners, six development companies and required extensive negotiations on Section 106 agreements.
In 1981 he co-founded the Chapman Warren Partnership that was instructed on a varied and extensive range of work in the residential, commercial, retail, industrial and leisure sectors for a diverse clientele including Barratt, Wimpey, Sainsburys, Tesco, Asda, Heinz, Grosvenor Estates, Rank and the Salvation Army. In the 1990’s the practice began to be instructed by the public sector including the MOD, Local Government, Development Agencies and the Home Office. In the latter case Graham Warren was central to obtaining planning permission for Secure Training Centres for Persistent Juvenile Offenders and had direct contact with Ministers involved in the programme.
Throughout the 1990s and to date Graham has continued to be involved in a varied portfolio of projects, giving evidence to public inquiries and negotiating planning permission. He has also been involved in Purchase Notices (compulsory purchase in reverse), Enforcement Cases, obtaining Certificates of Established Use and the lifting of Agricultural Occupancy Conditions. Projects range from single dwelling houses to promoting major planned urban extensions on large mixed sites.