In-form Colchester dominated throughout a one-sided match as they continued their push towards the promotion play-offs.
An inspired Greg Halford scored a marvellous brace of goals as did on-loan striker Jamie Cureton with defender Wayne Brown adding the fifth.
Incredibly it could have been a lot worse for Gillingham who were indebted to the good display of goalkeeping from an over worked Tony Bullock.
This was the first time that Colchester had won six games on the bounce since 1987 and they showed no sign of it being ended just yet.
Halford broke the deadlock in the 32nd minute to begin what unfolded to be a nightmarish afternoon for Gillingham caretaker manager Ronnie Jepson.
Kevin Watson and Chris Iwelumo exchange a one-two before Watson threaded a pass through to Halford. The 20-year-old lifted his shot over Bullock to notch his seventh goal of the season.
It was goal number eight for Halford in the 52nd minute. The midfielder scored a contender for goal of the season by unleashing a 25-yard shot that rocketed past Bullock and crashed into the net via the underside of the bar.
One minute later Colchester were three up. Cureton latched on to a loose ball and beat Bullock from the edge of the box with a deadly finish.
Swindon Town loanee Cureton scored his second and the U's fourth in the 66th minute and this time Halford was the creator with a cross that Leon Johnson could only deflect enabling Cureton to sweep home from inside the six-yard box.
Gillingham were all at sea and the U's added a fifth goal in the 70th minute. The visitors could not deal with a corner delivered by Watson and although they managed to charge down Liam Chilvers' close-range shot, fellow defender Brown rammed home from eight yards out.