After being released from Wigan Warriors he went on to join National League One side Widnes Vikings. He was one of seven ex-Wigan players in the 2006 Widnes side and regularly played in the second row. He played in the 2006 National League One Grand Final where Widnes lost 16–29 to Hull Kingston Rovers. At the end of 2006 his contract with Widnes was not renewed after he failed a drug test following the Grand Final game against the Hull KR. Allen was banned from rugby league for 12 months by the Rugby Football League after testing positive for a metabolite of cocaine, doubled to two years following an appeal by UK Sport.