Adrian Allen made his debut for Leyton Pennant towards the tail end of the 1998-9 season when he came on as a substitute in a 4-1 win over Wembley in the Isthmian League Division One.

He quickly established himself in the first team squad, and helped the cause with four goals by the end of the season, including two in the 7-2 Eastern Floodlit Cup victory over Tiptree United.

Following the departure of top scorers Billy Cove and Billy Read, Allen was handed the number 10 shirt at the start of 1999-2000, and grasped his opportunity with both hands, scoring six goals in the first five games of the season. He’d go on to score 17 in 30 games for Pennant.

His final appearance for the club was a 3-0 defeat to Grays Athletic in January 2000.

He moved on to Maidenhead United, where he spent two seasons before a season at Hampton & Richmond and one at Chelmsford City, where he scored 7 goals in 30 games.

Another season at Maidenhead followed, but he was back in Essex when Billericay Town moved in to secure his services, replacing Nathan Elder, the who joined then-League One club Brighton & Hove Albion.