In 2015, one of these encampments, unofficially named the Calais Jungle, drew wide attention due to its size as a result of the 2015 European migrant crisis.

[6] On 28 December 2018, Home Secretary Sajid Javid declared a major incident as rising numbers of migrants made crossings via boat; he warned there was a serious risk of people losing their lives as the Strait of Dover was one of the world’s busiest shipping lanes.

A total of 297 migrants crossed the channel during the year and organised criminal gangs of people smugglers were accused of being responsible.

The increase was blamed on improved security at ports and the Channel Tunnel which drove migrants to cross via the sea.

[8] She also appointed former Royal Marine Dan O’Mahoney the Clandestine Channel Threat Commander, a new role to lead the UK's response to tackle migrant crossings.

[16][1] The over-arching aim of Operation Isotrope was said to be deterrence, in addition to the interception of any boats to prevent illegal migrants from landing on UK shores.

Since the operation began, only a single known migrant vessel has made it to British shores without a naval or Border Force escort.

[2] Retired Vice Admiral and former head of the Border Force Charles Montgomery criticised the government's strategy, stating that Royal Navy ships would be a "honeypot" for migrants and would make crossings attractive.

[23] In an interview with France 3, Mayor of Calais Natacha Bouchart described the British government's deployment of the Royal Navy as a "declaration of maritime war" which would prolong her city's economic suffering and worsen the humanitarian situation.