He said, "I have thoroughly enjoyed my time at the Arms Park. In the ideal world I would have hoped to stay for at least another couple of seasons and settle here but the time is right for me to begin the transition from a full-time player to a professional career off the field.
"I have nearly completed my Master's degree and there is a real opportunity for me to establish myself in sports' development. The part-time contract at Bedford allows me to do that and to secure my future while my family will also be moving back to be near family and friends."
Matt Allen joined the Cardiff club in September 2001 having already played for England in uncapped matches and also for England A as well as the Barbarians against the Wallabies. He was an ever-present in the Northampton Saints team that won the Heineken Cup by beating Munster 9-8 at Twickenham in May 2000.
In his first season at the Arms Park he played in 30 of the 33 games to comfortably qualify for his club cap. His current record for the club and Cardiff Blues is 12 tries in 74 games. He features in the 22-man squad for this evening's match against Gwent Dragons.
Cardiff Blues' chief executive Robert Norster said, "Matt has been a loyal and committed player for us. He always gives 110 per cent on the field and has a mature approach off it. He has been an asset to the club and now the region and he returns to the East Midlands with our best wishes."