A large increase has been revealed in the number of illegal immigrants detained or arrested by police at one of Britain's main gateways.
Figures have emerged showing that 563 were held or arrested by Port of Dover police officers last year, up from 148 in 2013.
In 2012, the number stood at 105, while 46 were detained or arrested between January and April this year.
The figures, obtained under the Freedom of Information Act by BBC Radio Kent, give some illustration into the rising numbers of migrants trying to reach the UK.
Road Haulage Association chief executive Richard Burnett, who recently visited Calais, said migrants are going to great lengths to cross the Channel, even climbing into tankers.
He told Radio Kent: "They think it's a great place to be and (Britain's) their target. They will do anything they possibly can to get into the UK."
Government officials say law and order in and around Calais is France's responsibility, but the UK works with its cross-Channel counterparts to strengthen border security.
A Home Office spokesman said: "Last year we foiled nearly 40,000 attempts to cross the Channel illegally, more than double the number prevented the previous year.
"We are providing funding to bolster the security of ports in northern France and Belgium, including a £2 million upgrade of detection technology, a £1 million extension of dog searching capacity and £12 million to reinforce security at Calais and other ports.
"During the current period of disruption to cross-Channel services, Border Force has put its contingency plans into operation to ensure security is maintained.
"We have deployed additional Border Force staff and sniffer dogs in northern France as well as bolstering screening checks at Dover for both tourist and freight vehicles.
"This is on top of our already rigorous border controls, which include 100% freight screening at Coquelles and Calais."
The figures emerged following a weekend of further disruption to cross-Channel services when around 150 migrants tried to storm the Channel Tunnel terminal in France.
Services were delayed and cancelled after migrants accessed restricted areas on the French side, Chunnel operator Eurotunnel said.
Around 3,000 migrants from countries including Eritrea, Syria and Afghanistan are camped at a site dubbed "the Jungle II" near the Port of Calais.
French aid workers have reported a "catastrophic" situation there, with predictions that some 2,000 more migrants could arrive over the summer.
Volunteers from l'Auberge des Migrants say up to 50 new migrants are arriving every day at the camp, and there are not enough tents, blankets or food.
Hauliers have been advised by the Freight Transport Association (FTA) not to stop within about 60 miles (97km) of Calais, to stick with other drivers and make sure padlocks are always kept on vehicles.
The Port of Dover Police is a small, non-Home Office constabulary funded entirely by the port authority, Dover Harbour Board, to provide policing at the port.
Port of Dover Police are not responsible for border security, which is down to the Border Agency and Kent Police frontier operations.