 Lester is best known for his influence on race relations legislation in the United Kingdom through his status as a founder-member of groups such as the Institute of Race Relations, the Campaign Against Racial Discrimination and the Runnymede Trust.Lester has also been a prominent figure in promoting birth control and abortion through the Family Planning Association, in particular he is noted for his involvement in Northern Ireland affairs in relation to this.Lester resigned from the House of Lords after historic accusations of sexual harassment were made by Jasvinder Sanghera.