Wiltshire adventurer David Hempleman-Adams has failed in his bid to retain his world ballooning crown.

His gas-filled balloon landed in Serbia on Wednesday morning, having travelled 2,009 km since leaving Bristol on Saturday night.

Mr Hempleman-Adams, of Lacock, first won the Gordon Bennett Gas Balloon Race two years ago and was defending the title. But he and his co-pilot Simon Carey were pipped by just 426 km, with the Swiss team of Kurt Frieden and Pascal Witpraechtiger currently in first place.

The German team of Willi Elmers and Ullrich Seel were second in the race to see how far the teams can get on one fill of hydrogen, just 122 km behind.

All but one of the 20 teams has been accounted for, with the US team of Richard Abruzzo and Carol Rymer Davis missing over the Adriatic Sea.

When contact was lost with the Americans they had travelled 1,758 km - and if they are still in the competition they are the only team that can pip the Swiss.

Jon Mason, who was Mr Hempleman-Adams' co-pilot in 2008 and is now his flight controller, said the pair had landed safely on Wednesday morning in Serbia.

"David and Simon have landed safely in woodland and had to use the trees to break the speed up," he wrote. "They sounded out of breath but relieved and happy. They were flying at low level and the weather was coming in so the time was right. They landed in a place called Nis in Serbia - nice. We'll get David's take on the landing once he's caught his breath."

Mr Hempleman-Adams and Mr Carey, a Virgin airline pilot from Wiltshire, have endured freezing temperatures and hair-raising moments in the tiny balloon basket, which is just 1.2 metres square - the size of two school desks pushed together.

Pilots from 12 countries, including six from the UK, took part in the 54th race, which was first organised by James Gordon Bennett Junior in 1906.

The rules of the race are simple. Take off from a fixed point and fly as far as you can on one fill of hydrogen. The balloons can be controlled only by releasing gas to go down and throwing out sand to go up.