Illegal immigrant caught hanging on to the underside of a horse box from Calais to Dover Horse Valegro won gold with rider Charlotte Dujardin at London 2012 It was being taken back to England following an event in Norway Police with sniffer dogs found the immigrant before the vehicle left France An illegal immigrant was caught hanging on to the underside of a horse box transporting an Olympic gold medal-winning racehorse from Calais to Dover. The man was found clinging to the chassis of the horse box carrying Valegro, which won gold with rider Charlotte Dujardin at the London Olympics in 2012. Police with sniffer dogs caught the man, who had chosen the largest and most accessible vehicle in the queue, as the vehicle was readying to return to England after an event in Norway. Stowaway: An illegal immigrant was caught hanging on to the horse box carrying Valegro, pictured, which won gold with rider Charlotte Dujardin in dressage at the London Olympics in 2012, pictured above Groom Alan Davies said: 'We had queued at a manned booth to check in for the train, with just a couple of cars in front of us, and after checking in we were told to pull over once we'd gone through the barrier. I thought they just wanted to check the gas was off as they do on the trains, but security came over and looked under the lorry. They then said: "There's someone under there." 'They'd seen him on CCTV waiting around and when he'd disappeared they became suspicious.' Mr Davies said that he was shocked by what happened as he had taken precautions to guard against stowaways. If a trucker is caught with migrants in his vehicle when on British soil it is the driver, not the company, who is liable for a £2,000 fine. He told Horse & Hound: 'We were allowed to go - but if I'd gone through any further then I would've been fined. 'I've seen migrants hanging around in groups before, it was a big shock.' Valegro, who won Olympic gold at the London Games in 2012, had been returning from a demonstration event in Norway on Wednesday October 22. Dangerous: Police with sniffer dogs caught the man as the vehicle was readying to return to England after an event in Norway. Above, migrants in Calais try to jump on to a lorry before it crosses the Channel Migrants are flocking to Calais in increasing numbers this year, with up to 2,000 people living in makeshift shelters as they wait to cross the English channel. The impoverished conditions in the port city has lead Natacha Bouchart, the mayor of Calais, to announce a new refuge for migrants, likened by many to the infamous Red Cross camp at Sangatte. The failed camp acted as a base of operations for many trying to cross in the UK before it was closed in 2002. French authorities insist they have been left with few options after fighting between migrant groups lead to 70 people being injured this summer, while people have also been targeted by criminals. Just last month a crew aboard a P&O ferry were forced to turn a firehose on a crowd of around 250 people as they tried to force their way on to the boat. Suspicious: Police had seen the migrant on CCTV as he waited near the queue of vehicles and went to investigate when he disappeared. Above, desperate migrants try to board a truck from Calais to England The lorry driver who filmed the chaotic attempt to board the ferry, bound for Dover, described Calais as a 'war zone' saying the situation was at its worst for 20 years. A Home Office spokesman said: 'The security of the border is a priority and we are working at European and international level to address the wider problem of illegal migration. We have increased joint intelligence work with the French to target the organised crime gangs behind smuggling and people trafficking. These criminals are constantly modifying their tactics in an attempt to evade strengthened border controls and we are seeing increasingly dangerous methods being used, including the use of sealed or refrigerated vehicles. We warn those who are tempted to put their lives in the hands of organised criminals that they are putting themselves and their families at risk. If people have a genuine need of protection they should claim asylum in the first safe country they reach. British dressage rider Carl Hester MBE, part of the 2012 team, tweeted: 'Valegro arrived safely back at Folkestone unlike the illegal immigrant found underneath the lorry!'