Allan joined local side Carlisle United at the age of 12. He went on to play for the first team over 30 times and scored several goals helping the Cumbrians avoid relegation from the old Division Three. Allan moved to Northwich Victoriain 2002. Allan scored 75 goals in 220 appearances for Northwich.
Allan spent a brief period at Halifax Town at the end of the 2003–04 season before returning to Northwich.[2][3]
Allan was Northwich's top goal scorer as they won the Conference North division in 2006. This culminated with two goals against Northwich's nearest challengers, Stafford Rangers, on the penultimate day of the 2005–06 season. The game saw Northwich clinch the league, witnessed by over 3,000 spectators (a new Conference North record). In the 2008–09 season, Allan was injured for much of the campaign but came back strongly and finished as the Vics' top scorer under the management team of Andy Preece and Andy Morrison.
With the uncertainty regarding Northwich's future during the summer of 2009 there was rumoured interest in Allan's services. However, he stayed at the club determined to overhaul the ten-point deduction the Vics faced for the Conference North campaign. After the season in which Vics finished 12th he sought a move away for the off-field problems at Northwich.
On 26 May 2010, Allan signed for Conference National side Gateshead on a one-year contract.[4] Allan made his debut for Gateshead on 17 August 2010 as a late substitute away at Barrow. Allan made four appearances in all competitions for Gateshead during the 2010–11 season before his release on 4 May 2011.[5]