As a player, he was a midfielder notably playing top flight football for Tottenham Hotspur, Swindon Town and West Ham United, with appearances for both the Robins and the Hammers coming in the Premier League.

Following retirement, he became chairman of non-league side Grays Athletic, whilst at the club he hired Julian Dicks as manager and Peter Shreeves as director of football.

After playing in Tottenham Hotspur's reserve side and having been loaned to several clubs, Swindon Town manager Glenn Hoddle signed Moncur for £80,000 fee, towards the end of the 1991/92 season.

Despite this, he became something of a cult figure at Upton Park due to his committed attitude and occasional flash of brilliance as well as reports of his humorous off-field antics.

An indication of his popularity came in a fiery London derby against his former club Tottenham Hotspur on 24 April 1999 when he was sent off for two bookable offences, the latter a bad foul, and clenched his fists in defiance to the travelling West Ham supporters.

In 2009 he became chairman of non-league side Grays Athletic, whilst at the club he hired Julian Dicks as manager and Peter Shreeves as director of football.