Is it a bird? Is it a plane? No - it's a super-size airship carrying one man in a caravan as part of a gravity-defying stunt being filmed for TV's popular Top Gear show.

Is it a bird? Is it a plane? No - it's a super-size airship carrying one man in a caravan as part of a gravity-defying stunt being filmed for TV's popular Top Gear show.

Plane spotters training their binoculars to the skies above Norwich International airport early yesterday morning certainly got more than they bargained for as filming got under way for the unusual stunt.

Top Gear is renowned for its dangerous four-wheeled frolics, which have become a feature of the BBC's much-loved Sunday night show.

Presenter Richard Hammond narrowly escaped death and suffered a brain injury following a 300mph jet car crash while filming for the BBC2 show in September 2006.

Fortunately for fellow presenter James May, there was no need for the emergency services to intervene this time as the stunt appeared to go to plan.

It was an early start for May and the rest of the crew at Norwich airport where the stunt was being filmed.

It was a change of scenery and location for May and the rest of the Top Gear crew who were in Cambridgeshire last month to film the segment for the show when the airship crash landed.

Strong winds blew the airship off course away from its cricket pitch destination into a farmer's field near the A428. Emergency services were on hand, but not needed following the crash from which May emerged unscathed.

But the accident proved to be just a blip for the orange blimp and its fearless passenger May, who dangled precariously below the huge craft in a white caravan.

Rescue teams and the airport's security services arrived at daybreak at the airport yesterday to ensure that this time the stunt went without a hitch.

At about 6.45am crews started to inflate the huge airship, which within half an hour had dwarfed the two passenger planes which were parked nearby.

By 7.20am the Norfolk police helicopter, which had a cameo part to play in the scene, scrambled into a standby position near the blimp.

Shortly afterwards a second helicopter, painted blue and sporting the slogan "Flying TV HD", took up a position to the rear of the ship which by this time had huge blue fins to help guide it round the airstrip.

As air continued to fill the craft, an assortment of vehicles - some safety, some security, and some crew - surrounded the ever-expanding vessel as final preparations were made.

Then, some 45 minutes after air was first pumped into the ship, an engine that sounded like a tractor spluttered into life and the enormous bright orange ball slowly began to lift off the ground - revealing for the first time the tiny white caravan underneath.

For almost an hour, the airship with May and the caravan hanging on underneath, circled slowly above the airfield, rising and falling as it did so.

At one point the huge craft looked to venture perilously close to a nearby telecommunications mast, but both the ship and its caravan cargo avoided contact and carried safely on its way.

Fire crews arrived with sirens blazing at about 8.15pm prompting fears that the caravan might be dropped to the floor in an explosive finale to the stunt.

But thankfully both May and the caravan remained latched to the belly of the airship and came to land slowly, but safely, at just after 8.20am.

A spokesman for Norwich International airport said: "We were happy to support Top Gear in a test flight of a unique airborne vehicle, which has been approved by the Civil Aviation Authority (CAA), for a feature in an upcoming show."

The spokesman, who could not go into detail about the specifics of the stunt, did however confirm that May had been present at the airfield, although fellow presenters Hammond and Jeremy Clarkson were not there.

A spokesman for Norfolk police confirmed that the police helicopter had been used in the stunt following a request from the producers of the show. However, he stressed there was no cost to the force and that the producers were made aware that any operational policing matters would take precedence over the show's requirements.

No one from Top Gear was available for comment.