Career
Allen signed for Chelsea on his 17th birthday in September 1954 but never established his place in the Chelsea first-team He scored 12 League goals for Chelsea in 44 appearances before joining Tottenham Hotspur in December 1959. He scored 47 league goals in 119 appearances, but struggled to retain his place following the arrival of Jimmy Greaves.
He joined Queens Park Rangers in July 1965 and scored 55 goals in 123 starts and five substitute appearances.
He briefly managed QPR during the 1969-1970 season. In November 1972 he became manager of Swindon Town, remaining in charge until 1974.