An app called "flightradar24" was used by reporters of The Mail On Sunday to track Prince William as he went about his new job as an air ambulance pilot.

Costing just £2.99 ($4.65), the app allowed reporters of The Mail to keep track of the prince as he flew with East Anglian Air Ambulance in eastern England, creating a high level royal security breach, reports Al Jazeera. In fact, for a little extra charge, the reporters received a text alert every time the helicopter William used took off on a mission.

A former commander of specialist operations at Scotland Yard and an ex-head of the Flying Squad, Roy Ramm, called for action to shut down the security loophole immediately. "Knowing the precise movements, altitude and speed of an aircraft in flight is intelligence gold for any terrorist. The ability to track a high-profile target like this presents a really serious risk. Even without expensive and sophisticated weaponry, there is the real danger that an inexpensive drone could be used to put any aircraft flown by William at risk. There is also the risk that a terrorist might simply open fire on his aircraft at low altitude with the kind of automatic weapon readily available to gangs in London. After all, the Prince is flying an air ambulance, not an armoured gunship," he said, according to The Daily Mail.

The app would allow any terrorist armed with a rocket-propelled grenade, ground-to-air missile or even less sophisticated weaponry to target William's aircraft which regularly flies below 1,500 ft. with a cruising speed of just 150 m.p.h., said The Daily Mail.

Meanwhile, the former head of the Met's Royalty Protection Squad, Dai Davies, said, "This would give me cause for concern and solutions need to be found by those in charge of the prince's security. You always have to be aware of the advance of technology - which this illustrates - and the ability of these terrorist groups to think outside the box. You always, always have to be one step ahead," reports The Independent.

Buckingham Palace and the Metropolitan police have not responded to the claims, nor have the app's manufacturers. East Anglian Air Ambulances is operated by The Bond Aviation Group and the conpany said it could not comment on security arrangements.