The criminal threat to London’s wealthiest footballers is now so serious that they are hiring military drivers, bringing in more guard dogs, and could face new insurance clauses in their club contracts, experts have said.

Security providers who have worked with ultra-wealthy residents of the capital contacted after it was revealed that two Arsenal players faced an “ongoing security threat” related to an attempted carjacking said that a growing number of violent attacks had made their clientele increasingly wary.

Mesut Özil and Sead Kolašinac were left out of the north London club’s team against Newcastle last week after two men were arrested outside Özil’s home. That incident followed the attempted carjacking by an armed gang with mopeds when the two men were travelling together.

While both players – now believed to be under 24-hour protection – are expected to line up on Saturday against Burnley, the episode has lifted the lid on a hitherto little noticed new trend in a city that has long traded on a reputation for being a safe bolthole for the wealthy.

In areas like Hampstead Garden Suburb, home to high net worth individuals and a cohort of footballers including Özil, the security gates are getting higher and private security firms busier amid heightened security concerns, fuelled by a spate of sometimes violent home invasions and vehicle-enabled ram raids. Wealthy visitors to the city are also taking measures.

“We have seen a large increase in requests from our international clients visiting London asking for highly trained drivers with military backgrounds, who can act as both driver and security when required during short stays in the city,” said Samuel Martin, co-founder of 19 London, an international agency providing staff in homes, offices, yachts and private aircraft for high net worth and high-profile individuals.

Martin added: “I live in Hampstead and although private security here is fairly normal to see, our streets have definitely seen a large increase in security and guard dogs protecting homes of local residents in recent weeks due to the amount of violent attacks on neighbouring homes.”

Within the footballing community meanwhile, the ripples from Özil and Kolašinac’s experience continue to be felt.

“You can go back to all the burglaries in the past against players, Steven Gerrard or John Terry for example, but it’s a fact that there is an increasing crime wave at the moment in London,” said Paul Macarthur, the director of SGC Security, which provides services including event security, bodyguards and counter-surveillance.

Macarthur, whose clients include a Premier League club, predicted that insurance companies “sooner or later” would start to talk to teams about inserting clauses into contracts to covering the security threats faced by players worth tens of millions of pounds.

“When they’re in the training ground there will be full-time security but the minute they leave that comfort zone it changes. You’re talking about multimillion-pound assets, who also often have a significant social media footprint and very visible signs of wealth like flashy watches and cars. In many ways, they’re easy prey.”

On any day, security outside some of the more exclusive addresses just north of Hampstead is apparent. Uniformed private security personnel patrol on foot or in vans belonging to companies reporting an upsurge in demand, while CCTV cameras are visible on poles behind subtly sculpted gates and fences.

Facebook Twitter Pinterest A private road in Highgate, London. Photograph: Antonio Olmos/The Observer

“In some areas what you’ve basically got are high net worth individuals or, say, 10 properties who have clubbed together and formed private tenant associations that employ security as a high visibility deterrent. If a resident is going away on holiday they’ll act a keyholder, take in packages and turn on lights at night,” said one.

“Prices per year could be in the region of £30-40,000. You’ve basically got gated communities like the US with private police operating as police resources are cut.”

At another level too, personal bodyguards are typically earning about £500 a day for work in a sector that has become a popular source of employment for ex-military personnel.

On the streets north of Hampstead, not everyone is pleased with the direction of travel.

“This is a conservation area but its character has definitely changed in the past year or so and perhaps it’s a pity,” said one long-term local resident during the week as he walked his dogs close to the home of Özil, where three sleek German-registered sports cars sat behind the property’s wall.

“What tends to happen is that a home might be demolished and when it gets rebuilt again there might be a large security gate. It obviously looks different from the older homes,” he added, gesturing to one side at an older, open-fronted, red-brick home and then to the other side, where major construction works were shrouded by metal hoarding.

If some recent experiences are anything to go by, those living here do have reason to be fearful. While security is at its tightest on streets such as the Bishops Avenue – for long nicknamed “Billionaires’ Row” – and on two nearby private streets which are closed off by barriers, it hasn’t stopped thieves in other locations from using four-wheel drives to knock down gates and break into homes, often in the full knowledge that they may be occupied.

Raids included one on the home of the historian Andrew Dutton Parish by masked robbers armed with machetes, who stole £20,000 of designer watches as he hosted a dinner party in July. A gang carrying machetes also robbed the former Tottenham forward Ronny Rosenthal in Cricklewood earlier in the summer, making off again with designer watches.

Mike Freer, the MP for Finchley and Golders Green, said a number of covert operations were in place but he claimed that police resources did not match the scale of the problem, claiming that boroughs such as Barnet ended up being shortchanged under resource allocations.

“We get fewer officers per head than most London boroughs,” he said. “The formula doesn’t reflect the extra demands on our local police in providing support to buildings and communities that are more vulnerable.”