March 2002: Joins Barnet as assistant manager.

March 2003: Takes over at Barnet in his first managerial role and leads the club to 20 wins in 47 matches.

March 2004: Leaves the Bees to take charge at Brentford and leads the club to two play-off finishes in the third tier.

May 2006: Resigns as Brentford boss citing a lack of investment in the team.

June 2006: Takes the helm at Milton Keynes Dons and guides the team to the League One play-offs but is again unable to secure promotion.

May 2007: Swaps MK Dons for Leicester City but falls out with chairman Milan Mandaric and leaves the Championship outfit after just four games in charge.

September 2008: Appointed manager at Cheltenham Town but the League Two side suspend him just over a year later while they investigate allegations he racially abused a nightclub bouncer. No action was taken concerning the incident. 

December 2009: Leaves Cheltenham Town and a month later becomes a part-time scout at Queens Park Rangers.

March 2011: Allen appointed on an eight-game contract but leaves after three matches to take charge at Notts County.

April 2011: Signs a one-year rolling contract at Notts County and steers the club clear of relegation from League One.

February 2012: Sacked by Notts County.

April 2012: Takes over at Barnet for a third time and leads the Bees clear of relegation with two wins from their final three games of the season.

June 2012: Contract at Barnet expires.

July 2012: Named manager of Gillingham and takes the club to the League Two title, securing a first promotion of his managerial career.

October 2013: Sacked by Gillingham after the team had won only two of its first 11 matches in League One.

March 2014: Appointed Barnet head coach for the fourth time with the Bees ninth in Skrill Premier and a point behind the play-offs.