An urgent security review is today under way at Gatwick amid claims a man smuggled a replica machine gun and pistol on to a plane.

The news comes just weeks after a man was arrested and charged over allegations that a hand grenade was found in his luggage at the Sussex airport.

BAA Gatwick's managing director Roger Cato said: "We take the security of our airport and the safety of passengers and staff extremely seriously.

"With the police, we've launched an immediate investigation into claims that a man was helped to gain access to secure areas of the airport by a member of staff from an airline catering company.

"We will be considering with the Department for Transport whether, in the light of the claims, there should be a further review of these procedures."

The allegation was made in a Sunday newspaper, which said a reporter was able to get past guards by hiding in a lorry supplying in-flight meals.

The driver of the vehicle reportedly agreed to help the investigation out of concern for lax security at the airport.

It is claimed the driver picked the reporter up and was supposed to secure the back door with a plastic seal but left the seal open, which apparently went unnoticed at the depot.

The driver was searched by security guards but, it is said, they did not check inside the lorry.

Once among the parked aircraft inside the secure cargo and freight area, the reporter and driver were able to board a 200-seat Monarch airlines aircraft standing unattended.

The pair then reportedly explored the plane, looking for hiding places for weapons, entered the cockpit and sat in the captain's chair. The driver photographed the reporter holding the fake M16 assault rifle and pistol.

They then wandered outside and watched planes taking off before returning to the truck and driving out unhindered just over an hour later.