He went on to work as an investigative reporter on BBC Radio Four's Checkpoint, probing into cocaine trafficking and murders carried out by the Sicilian Mafia.

Jennings consequently resigned and transposed the material into his first book, Scotland Yard's Cocaine Connection.

[5] Jennings subsequently worked for Granada, filming several international investigations and small documentaries.

His investigation of British participation in the Iran–Contra affair won the gold medal at the New York TV Festival in 1989.

[6] He worked with World in Action in 1997,[2] with an investigation on British Olympic swimming coach Hamilton Bland.

[8] Jennings's first appearance on Panorama, a current affairs documentary television programme, came in June 2006 (episode entitled "The Beautiful Bung: Corruption and the World Cup"): Jennings investigated several allegations of bribery within FIFA, including million-dollar bribes to secure marketing rights for the body's sports marketing company ISL along with vote-buying (to secure the position of FIFA president Sepp Blatter), bribery and graft attributed to CONCACAF president Jack Warner.