Armed officers stormed a historic home in Hampstead and police scrambled a helicopter after reports that guns had been fired in the area.

Police raided Grade I-listed Romney’s House in Holly Bush Hill at 2pm on Sunday after a concerned member of the public spotted an air rifle inside the 18th century home.

The Met’s Trojan unit – armed with automatic weapons – and several other officers cleared the building, which is currently being developed, in what neighbours described as a scene from a Hollywood blockbuster.

Builders who had been working on artist George Romney’s former home, which features a ballroom and assembly rooms, were rounded up by officers and questioned over the incident.

Retired IBM worker Sheila MacLeod, who has lived next door for more than 10 years, said: “The helicopter was hovering above and my whole house was rattling.

“That’s when I saw a guy crouched down against a car and he bobbed up suddenly in a flak jacket with a gun in his hand.

“I thought to myself ‘this must be pretty serious’ and I really thought we were going to see a shoot-out on our doorsteps.”

Hugo Rya, caretaker of neighbouring Heath Mansions, said residents were scared that a gunman would try and escape through their block of flats.

“There were sharpshooters stationed behind us in The Mount,” he said.

“We heard that people were in Romney’s House with a handgun and an air rifle.

“We were obviously worried that someone was going to try and come through our building.”

Police recovered a number of imitation firearms from the site and later destroyed them.

No-one was arrested and police are not investigating further.

A builder, who did not wish to be named, told the Ham&High: “It was just a false alarm. We had a BB gun (an air gun) and they took it away and that was that.”

Romney’s House has been a construction site for at least two years and this latest incident has tested neighbours’ patience.

“It’s never quiet here and we’re all just getting fed up,” said Mr Rya.

The historic house is owned by hedge fund manager Mark Smith and the old stable and coach house behind it were turned into The Holly Bush pub.

The Ham&High tried to contact Mr Smith but he did not return our emails.