IT WILL be the biggest soccer-related police operation ever staged in Hampshire.

A huge number of specially-trained officers will be duty at Fratton Park tomorrow when Saints take on Pompey in the third round of the Carabao Cup.

The bitter rivalry between the two sides - described by some as the most intense in football - has sparked fears of major crowd trouble.

Police will be using horses, helicopters and drones to help them prevent violence breaking out and deal with any incidents that do occur.

Assistant Chief Constable (AAC) Scott Chilton is leading the overall policing operation and has overseen all the planning.

Asked about the possibility of trouble he said: "The rivalry is intense and although the two teams haven't played each other for seven years there's always the potential for disruption.

"We have been working with both clubs and other partners to devise a very detailed police operation which is designed to ensure everyone's safety."

In a message to fans he added: "We want this match to be remembered for what happens on the pitch, not off it. Be passionate, enjoy the game and do your club proud."

Citing operational reasons ACC Chilton declined to say how many police would be on duty at the game.

But he said: "There will be a large number of officers using specialist tactics including, horses, helicopters and drones as well as intelligence-gathering techniques. Our priority is public safety and our message is clear - any disorder will not be tolerated."

The last time the two teams met at Fratton Park was in 2011.

Police implemented a controversial “bubble” scheme which involved all Saints fans having to catch designated coaches at one of three pick-up points.

They were dropped in a “sterile area”, which people were prevented from accessing unless they were one of the coaches, and escorted to Fratton Park.

As reported in the Daily Echo, police are not employing the same tactics this time around.

ACC Chilton said the previous fixture involved a Sunday lunchtime kick-off, whereas tomorrow's game started at 7.45pm, with fans travelling to Fratton Park during rush-hour.

"It's several years on and there are different police tactics as well as different dynamics," he said.

A Hampshire Constabulary spokesman added: "This is the largest-ever football policing operation in Hampshire and the public will see a significant police presence in and around Portsmouth."