Wiltshire adventurer David Hempleman-Adams is closing in on retaining his title in the world's oldest balloon race.

Mr Hempleman-Adams' balloon is one of three still flying - he is competing against American and German teams to see who will win the 54th Gordon Bennett Gas Balloon Race.

The adventurer, who lives in Lacock, is defending the title he won two years ago in the US.

On Saturday night 20 hydrogen-filled balloons took to the skies above Bristol with the simple aim of seeing who could go furthest.

After four nights of flying only three teams are left - but worryingly for Hempleman-Adams all have won the competition before.

The British adventurer won in 2008 with co-pilot Jon Mason, American Richard Abruzzo won in 2004 and Germany's Wilhelm Eimers in 2000.

To win they have to beat the marker set by the Swiss, who travelled 2,434km and landed in the far east of Romania.

By this morning Hempleman-Adams and his co-pilot Simon Carey had flown 1,970km and were south of Belgrade.

They 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.

On his blog Hempleman-Adams wrote: "It's been the coldest night with the low point being when some of the ballast froze in the bags.

"It was about -1C, so we've been shivering on and off. Our speed has been up and down and direction left and right.

"We've been on oxygen most of the night, mountainous terrain below.

We're now south of Belgrade with rain ahead of us which I want to avoid - there's nothing quite like being frozen and rained on in a balloon basket.

"I've had a lot of chats to Jon Mason about strategy and am trying to second guess what the Germans and Americans are doing.

"Jon says the Germans look like they're heading for Moldova and we've been trying to work out Abruzzo's tactics. Is he going for the Italian or Adriatic coast?

"This race is far from over."

Hempleman-Adams and Mason were the first British team to win the race in 2008 when they flew 1,098 miles in just over three days, from Albuquerque in New Mexico to the shores of Lake Michigan, north of Chicago.

Their victory earned them the right to host the race in their home country, and they picked Bristol as the launch site.

Some pilots are expected to be in their wicker baskets for up to five days, with the record distance of 2,112 miles being recorded in America in the 2005 event.

The event was first organised by James Gordon Bennett Junior in 1906.

To follow the team's progress, go to www.hempleman-careygb.co.uk/latest-blog-entries.