It is a scene that is played out with the regularity of clockwork. It's 11am and the first cars start to arrive at the Centro Plaza. One day a criminal will park in a spot to the north of the car park, the next he will go south and on the third day he will leave his BMW 100 yards up the road and walk.

Gangsters know they are meant to rotate their movements and regularly change their routine in case a gunman is waiting in the shadows. Whether they decide to drive or walk, wear a disguise of a hat and shades, or not, the Irish criminals are sitting ducks as they go down the steep stairs of Centro Plaza to the Plaza Gym below the swanky Yanx café and restaurant. They cannot help it; they are creatures of habit who lack the discipline to take the personal safety precautions the Russian mafia take for granted as part of their daily lives.

It is this little corner of Puerto Banus on the Spanish Costa del Sol that Irish criminals call home. It is little Ireland, where the likes of Fat Freddie, the Dapper Don and the Colonel feel safe and comfortable. They lead a pleasant life in near year-round sunshine with nothing to fear except the odd bit of interference from the local constabulary.

Until last week that is.

Most of the Irish drug dealers were tucked up safely in their beds when the first door was kicked in just after 4.30am last Tuesday morning. By mid-morning, 16 people had been detained in Spain, nine lifted in the UK and one man arrested by the gardaí. It was the culmination of Operation Shovel, an investigation that had been two years in the making and involved police forces around Europe.

The most significant work was done in Spain. Fifty-three year-old Christy Kinahan, the undisputed godfather of Irish organised crime and drug importation, was in cuffs along with his two sons. His closest associate, 59-year-old John 'The Colonel' Cunningham, who was responsible for the kidnap of Jennifer Guinness in 1986, was also behind bars.

It sent shockwaves not just across the Irish underworld but around continental Europe where Kinahan, nicknamed the Dapper Don, had become one of the biggest players over the last decade.

Kinahan is currently languishing in a Spanish jail while he waits to learn the case against him. His Spanish assets have been frozen and his business is in tatters.

For the smaller Irish criminal in Puerto Banus there is nothing that can be done so life goes on as normal. Each morning, expatriate Irish criminals and drug dealers head to the Plaza Gym. They have made sure to inject themselves with bodybuilding steroids while eating their breakfast of bananas and yoghurt. The Plaza is a very reputable and popular gym where, for the Irish, socialising is as important as pumping iron.

Almost every Irish criminal with links to the Spanish costas is a member here. Freddie Thompson received a bad beating outside the gym earlier this year following a row with a foreign criminal. For €56 a month, you can rub shoulders with gangsters from the UK, the Netherlands, not to mention Crumlin, Finglas, Limerick and Dublin's north-inner city.

Artificially pumped physiques and tattoos covering most of the arms are musts, as is the obligatory cup of coffee and light lunch in Yanx after a two-hour workout. It is at Yanx that the phones are produced. There is no suggestion that the owners are aware of the identities of their customers.

Each dealer generally has three or four phones on the go at once and 'rinses' them every few days so they cannot be bugged. A phone call here and there or a quick chat with the Russian or Turk and the day's work is done. The next shipment has been organised and the criminal can be happy in the knowledge that a large batch of cocaine or cannabis should arrive at Rosslare Port the following month and flood cities and towns around the country within a few days of arriving in Irish territory. The profits are such that a clever dealer could work from Spain for three years and make enough money to retire on – but it rarely works like that in gangland.

After lunch, the criminals go home and sunbathe for the afternoon and generally take it easy. Because a lot of Irish gangsters have fled Ireland, many of their families also live here and there are frequent visitors over from Dublin. The average drug dealer lives in a rented villa with a swimming pool and most nights they converge on the port of Puerto Banus to socialise around the string of Irish pubs, invariably ending up in Linekers, the area's most popular bar. Cocaine is readily available and invariably used and the party goes on till the early hours of the morning before they go home and sleep for a few hours before going back to the gym to get rid of the hangover. It is the same story every day.

Puerto Banus is a strange place, a microcosm of Irish society. Many well-known millionaire property developers – including Sean FitzPatrick – proudly call it a home-from-home. Hundreds of gardaí also own property here. It is not unusual to go to an outdoor bar down at the port and see the likes of a property developer sipping a glass of wine, a senior garda enjoying a beer a few yards away while a notorious criminal drinks a pint bottle of Bulmers at the next table.

The property developers and ordinary Irish citizens who own homes here are frustrated that the area has seemingly been taken over by the criminals. After negative media publicity following a shooting in 2008, the rental market dropped by nearly 15% because a lot of Irish visitors have stopped coming over, being put off by reports of gangsterism and open drug dealing. It is not as bad as it has been made out but drugs are easily bought and are hawked in bars that charge €7 for a pint of local beer.

Before its unwanted reputation as the central hub of the European drugs market, Puerto Banus was best-known as a playground for the rich and famous. Yachts worth tens of millions of euro crowd the harbour while prostitutes openly offer their services in almost every bar.

Years of inertia by the police mean Spain is regarded as a country that treats organised crime lightly so it is obviously an attractive place for Irish criminals. There were always underworld figures based in and around Puerto Banus but the criminal population has swelled in the last year. When Dermot Ahern introduced legislation last summer to allow for people to be convicted of membership of a criminal organisation on the word of a chief superintendent, it sent shivers down the spines of gangsters. They deserted Ireland in their droves, fearing they would be picked up and charged under the new laws. The majority ended up in Puerto Banus, with gardaí estimating that as many as 70 Irish criminals are now based there full time. The leader of one of the Crumlin/Drimnagh based gangs, Fat Freddie Thompson is here almost permanently, as are half a dozen of his senior lieutenants.

Sixteen people have been murdered in the Crumlin/Drimnagh feud, but members of the rival gang are now based here too and the two gangs coexist together peacefully. The attitude is that when they are in Dublin feuding is fair game but there is no point in bringing the hostilities to Spain with them.

The common link for these criminals is Christy Kinahan, the Mr Fixit. Not much business is done here without his involvement, knowledge or consent.

Two hundred yards away from Centro Plaza lies a luxury villa surrounded by high fences with CCTV monitoring the front gate. It is on a vast piece of land but beyond the imposing security measures, the five-bedroom villa is falling in to serious disrepair. Long grass covers what once was a perfectly manicured lawn, the outdoor swimming pool is black and debris floats on the surface of the water.

Inside, a few personal items have been left behind on the floor because the owner left in a hurry.

The owner in question is Peter 'Fatso' Mitchell, a 40-year-old originally from Dublin's north-inner city. He was a member of John Gilligan's gang and fled Ireland following the murder of journalist Veronica Guerin in 1996. He was until last year one of the lords of the Irish underworld in Spain. Regarded as being extremely close to both Christy Kinahan and John Cunningham, he was a loyal member of Kinahan's crime network. One of Fatso's closest friends is a former Premiership footballer who lives in Marbella and specialises in money laundering.

Fatso owned the Paparazzi bar just up the road from his home. Some of its customers read like a who's who of Irish and international drug dealers who met there to discuss business and mastermind drugs shipments. It was a busy spot and Mitchell made a very good living from the bar but the Spanish police were unhappy with what was going on there and began to pay it close attention, which frightened its less law-abiding clientele, who deserted it.

The Spanish police eventually succeeded in having the pub shut down permanently. There was worse to follow for Fatso though.

In August 2008 he was having a drink at the El Jardin garden bar just a few minutes' away from his home when a masked gunman approached and opened fire. Mitchell was hit twice in the shoulder and ran through the garden and managed to escape. Two innocent customers were injured by stray bullets.

It was widely believed that Fatso had a falling-out with a foreign gang but he was nervous enough that as soon as he was released from hospital he hastily cleared out his villa and promptly left Puerto Banus behind forever.

It emerged last week that Spanish police have been quizzing Christy Kinahan about that attempted murder and believe he was behind it. This would explain Fatso's hurried departure because Christy Kinahan is not a man to be messed with and is extremely ruthless, although he does have a reputation for favouring discourse over violence. He does not tolerate anything getting in the way of making money and Mitchell obviously knew this only too well.

The closure of Fatso Mitchell's pub by the Spanish police is evidence that the activities of international criminals have been on their radar for a long time. For the last two years they have been in constant contact with gardaí, sharing intelligence and preparing the ground for last week's arrests.

In many ways, Peter Mitchell's dilapidated villa is a symbol of the demise of Spain as a safe haven for Irish criminals. It is up for sale with an asking price of €1.2m and Fatso is hiding out in the Netherlands, probably terrified that whoever tried to kill him will come back to finish the job. His wife has returned to Dublin, swapping a life of Spanish luxury for her old job as a street trader.

If the Spanish police and gardaí and the other international police agencies have done the groundwork and built good cases against Christy Kinahan and his cohorts, then we may well see a major shift in the way drug dealers do business.

Last week's events have shown that Spain is no longer an easy touch and that large-scale drug importation will no longer be tolerated by the authorities.

It could close Marbella and the surrounding areas almost overnight and see them being abandoned by Irish criminals. What is the point in living somewhere if it is not a safe place from where to operate?

In the wake of the raids there was a mass exodus from Marbella, with the more senior criminals moving further up the coast to digest what had happened and assess its potential significance.

A Spanish judge last week froze the assets of Freddie Thompson and Gary Hutch – a nephew of 'The Monk' Gerry Hutch – and indicated he wanted to talk to them about the 2008 murder of their friend Paddy Doyle near Malaga.

This almost certainly means that both men will not be setting foot in Spain for the foreseeable future so they will now have to find a more relaxed country to base themselves in.

Other criminals will inevitably be forced to do likewise. Property belonging to Thompson and Hutch was searched in Spain last week, but the two men were in the Netherlands and avoided arrest.

There is now a good chance that Amsterdam will re-emerge as the new drug-dealing base of choice but the Dutch police are no pushovers and are very experienced in dealing with the drug cartels.

Time will tell but we may well and truly have turned a corner, with the balance of power shifting from the dealer to the authorities for the first time in a long time.