Flights at Britain's second largest air hub, London's Gatwick Airport, were disrupted on Friday when a hot-air balloon strayed into itsairspace, a spokeswoman said.

Five departing flights were affected after airspace was shut on safety grounds at the airport in Sussex, she said.

"Airspace was shut for safety reasons after a hot-air balloon strayed into the Horsham area," the spokeswoman said, adding that the airport reopened at 0820 GMT.

Gatwick is the busiest single-runway airport in the world, handling around 33 million passengers a year.