Christopher worked for NACRO from 1956 to 1998, from 1956 as member of council and from 1973 as chairman. He was member of the TUC General Council from 1976 to 1989 and its chairman in 1988 and 1989. For the Civil Service Building Society, he was director between 1958 and 1987, as well as chairman between 1978 and 1987. He was member of the Inner London Probation and After-care Committee from 1966 to 1979, of the Tax Reform Committee from 1974 to 1980 and of the Royal Commission on Distribution of Income and Wealth in 1978 and 1979. Christopher was also member of the Independent Broadcasting Authority from 1978 to 1983, of the council of the Institute of Manpower Studies from 1984 to 1989 and of the Economic and Social Research Council from 1985 to 1988. Between 1983 and 1986, he was chairman of the Tyre Industry Economic Development Council and between 1985 and 1990 vice-president of the Building Societies Association. In 1987 and 1988, he was director of the Birmingham Midshires Building Society. Christopher was further member of the General Medical Council (GMC) from 1989 to 1994, of the Audit Commission from 1989 to 1995 and of the Broadcasting Complaints Commission from 1989 to 1997.