Bradford's win moved them to within one point of League Two leaders Walsall in the race for the title
Calum Kavanagh and George Lapslie both scored twice as Bradford brushed aside promotion rivals Colchester.
The crowd of 23,381 was the largest at Valley Parade for a fourth-tier game and they witnessed a convincing home performance from the second-placed Bantams.
Neill Byrne headed just over as Bradford turned the screw in the first half before they took a 32nd-minute lead when Kavanagh prodded home Brad Halliday's centre.
Colchester equalised four minutes later with Harry Anderson lashing home the rebound after Jack Payne's shot was blocked.
But Lapslie restored the home side's advantage before the break, nodding in Tayo Adaramola's cross.
Colchester looked to respond again as Payne fired over from 20 yards and Owura Edwards slid the ball past the post after going clear.
Colchester keeper Matt Macey did well to claw away Romoney Crichlow's header but Kavanagh struck his second after good work from on-loan Birmingham midfielder Brandon Khela.
Lapslie then completed a double of his own when he slid in to convert a drilled by substitute Bobby Pointon and seal an emphatic win.
Report supplied by PA Media.
