During his time in Parliament, Oppenheim served in various ministerial posts in the governments of Margaret Thatcher and John Major and was also the parliamentary aide to Kenneth Clarke, the former Chancellor.

While in parliament, he was known for strong free-market and free trade as well as socially liberal views, including supporting animal welfare issues and opposing the sport of fox hunting.

As a Treasury minister, he toughened restrictions on imports of endangered species and introduced tax breaks on less-polluting fuels, including LPG.

Oppenheim was a keen sportsman, running for Belgrave Harriers and playing rugby for his constituency team, Amber Valley.

He has criticised new Labour's spin culture, along with what he saw as the corrupt sale of peerages, and the Conservative Party for its rightward and increasingly anti-EU drift.