When old football rivals Portsmouth and Southampton played each other in the FA Premiership seven years ago, the occasion turned into a tough match for the police.

Seemingly uninhibited by the presence of large numbers of officers, a hard core group of fans intent on trouble ran amok through Portsmouth city centre. There were ugly clashes in spree of violence that culminated in 90 arrests.

A subsequent match at St Mary’s in Southampton saw 12 people jailed – and with the memories of these difficult days etched into the minds of the Hampshire Constabulary contingent charged with the policing operation, a great deal of learning had fermented into a new action plan by the time the sides met again this season.

Despite both being relegated to the Championship, the potential for a premier league display of violence from the hard-core of troublemakers still remained – and this was a scenario that senior officers were not prepared to entertain.

Their concerns led them to consider a new tactic known as the “Swansea Bubble”. In base terms this meant that visiting Southampton fans would not be entertained if they turned up ad hoc at Portsmouth’s Fratton Park ground. Instead, they would have to buy a coach ticket before being bussed to the ground under a police escort, returning in the same way to Southampton following the match. Pubs would be closed before, during and after the game.

While the tactic – which was given its name after it was deployed in Wales during the often troublesome Swansea City v Cardiff matches –was simple in principle, the operational deployment meant a large commitment of resources. They included air support and the Force Roads Policing Unit as well as a serious ground commitment including mounted officers and dog units.

It was also an expensive undertaking – but in the view of Ground Commander Supt Ricky Burrows, an authority on football-related policing – worth every penny and subsidised to some extent by arrangements with Portsmouth FC. “This was in the planning stages for two months and we spent considerable time on it,” he said. “The plan included the deployment of ten PSUs as well as mounted officers from Thames Valley Police brought in under collaboration arrangements with the Force.

“We decided to try something different because our previous tactics simply had not worked and there was disorder whenever the two sides met – our aim was to create a completely sterile area near the ground to receive the Southampton fans arriving in two convoys of coaches. From there we could allow them to safely enter Fratton Park to watch the match.”

In tandem with the escort operation, bridges over the route of the two coach convoys were secured by officers and potential flashpoints were monitored by the Force helicopter. A robust tactical plan covered the potential for trouble in the ground with a raft of scenarios in the event of a pitch invasion.

The command chain for the operation saw an Assistant Chief in the Gold role plus a Silver Commander complementing Supt Burrows’ critical presence on the ground. Two inspectors experienced in public order situations were Bronze Commanders.

The meticulous planning certainly paid off. Despite some robust verbal insults between Southampton fans and Portsmouth residents en route to the ground, both convoys arrived safely in the sterile area and the visiting fans were inside the ground within 45 minutes. The operation was watched by a legion of observers, including officers from the Danish police, NPIA, Hampshire Police Authority and the Crown Prosecution Service.

Nick Hawkins, Chief Crown Prosecutor for the Wessex Area and the National CPS Lead on football related incidents, said: “For both police and the CPS, this type of operation is about planning for every eventuality.

“We were kept fully informed and had lawyers available on match day so we could react to any trouble immediately. This enabled us make sure that we knew what evidence was available quickly in the event of any incident.”

Robert Purkiss, a member of Hampshire Police Authority and former top-flight football referee, was convinced that the Swansea Bubble operation was necessary given the history of violence between rival Portsmouth and Southampton fans.

“Clearly there was a significant cost attached to this operation, but this outweighed the costs of doing nothing,” he said. “The first duty we have is to protect the public – the vast majority of people are not involved in hooliganism.

“There was significant disorder following a match between the two sides in 2004, when there were 90 arrests – then there was a huge cost to policing.”

Despite being played against the customary torrent of taunting between both sets of fans, order was maintained within the ground during the 90-minutes of play with only a few fans requiring police attention for their over zealous insults. The game finished 1-1, with Southampton’s visiting contingent shepherded from the ground and to the coaches parked outside the ground on the final whistle.

PC Paul Foley, a Football Intelligence Officer with Hampshire Constabulary, was impressed with the effectiveness of the plan in keeping would-be troublemakers apart.

“The operation was massively focused on the movement of the away supporters and to that extent my role was somewhat reduced,” he said. “The fans had never experienced anything like this before so they didn’t really know what to expect.

“The plan went very well and benefited from a great deal of planning involving Portsmouth and Southampton football clubs,” he added. “While there was some unhappiness, most of the fans thought this was a good idea.”

The verbal goading, chanting and singing continued after the game, but the sterile area prevailed and it was not long before the Southampton fans were on the busses home. The day finished without any football related incidents.

There was certainly a great deal of learning out of the day. Having now served football related policing well in Wales and southern England, the Danish observers took the Swansea Bubble home as an example of best practice for their own flashpoint match.

A spokesman for the Danish contingent said that the tactic could be deployed for games between FC Copenhagen and Brondbui, where violence had traditionally flared.

“From what we saw, this operation cut down to opportunities for disorder to take place, so it is something we are going to be reporting back on,” he added. “We think it will bring great benefits for both clubs and the police.”

The Swansea Bubble is might be an expensive option, but when carried off successfully it delivers the right result. Its deployment in Hampshire shows that it can be adapted to suit the needs of a local derby where distances between the clubs are short and the right transport options are available.

What is clear is that tactical plan must be robust and implemented with thoroughness for it to be a success. But the tactic’s use at Fratton Park goes to show that, when successful, the bona fide football fan is the clear winner.