His initial athletics breakthrough came at the World Junior Championships in 1992 as part of the British 4 × 400 metres relay team that finished fifth.

Thomas attended Stamford School and West London Institute of Higher Education, where he studied Sports Science and Geography.

At the 1996 Olympic Games in Atlanta, Thomas finished fifth in the final and took a silver medal in the 4 × 400m event (in which the team broke the European record, which stood until 2024).

However, in 2008, US team member Antonio Pettigrew, who ran the second leg of the final, testified in the court case against trainer Trevor Graham that he had been aided by performance- enhancing substances between 1997 and 2001, including the 1997 World Championships.

Thomas was selected in 2006 for the Welsh team for the 2006 Commonwealth Games in Melbourne, Australia, but was unable to compete due to an injury.

His father was born to Welsh-born parents in Middlesex, whilst his mother's Welsh language speaking family were centred around the village of Llandderfel, Gwynedd.

[citation needed] Iwan took part in the celebrity games of the Million Pound Drop Live broadcast on Friday 10 August 2012.

Thomas made a guest appearance as a cyclist at the final round of the 2008-09 Revolution series at Manchester Velodrome, competing in the 200m time trial.

Teaming up with former professional footballer David Prutton, the pair discuss all things two wheels and welcome a host of celebrity guests on the show.