Carter stood for Parliament in Basingstoke at the 1970 general election, without success, defeated by Conservative politician David Mitchell.

He was nominated as a Labour "working peer" by Neil Kinnock, and raised to a life peerage as Baron Carter, of Devizes in the County of Wiltshire, on 23 March 1987.

In 2001 Sky News investigative journalist Gerard Tubb revealed Denis Carter's farming company was linked to illegal sales of swill fed pigs to a major supermarket supplier.

In 2002 Sky News showed video of pigs kept in sow stalls on the company's Wiltshire farm, a practice which had been banned in the UK during his time in government.

[3] As a result of this, the parents set up the Andrew and Catherine Carter Foundation Trust to help disabled people.