Table of Contents
Migration that takes place outside legal channels, including Channel crossings, clandestine entry, overstaying, and people smuggling.
Irregular migration / unauthorised migration
Migration that takes place outside official, legal channels. In the UK context, it includes clandestine entry, Channel crossings in small boats, visa overstaying, and remaining after failed asylum claims. The true scale is unknown. The Home Office uses “irregular” and “unauthorised” interchangeably; the term “illegal” is also widely used in political and media contexts.
Small boat / Channel crossings
The crossing of the English Channel in small vessels — typically inflatable dinghies or rigid-hulled inflatables — by people seeking to reach the UK without authorisation. Numbers rose sharply from 2018, reaching a peak of around 46,000 in 2022. Around 94% of those who arrive this way subsequently claim asylum. The issue has dominated UK immigration policy debate throughout the 2020s.
Clandestine entry
Entry to the UK by concealment, typically by hiding in lorries, shipping containers, or ferries without detection. Before the rise of small boat crossings, this was the most common form of irregular entry. Detection has become harder as smuggling networks have professionalised, though significant enforcement resources are deployed at UK and French ports.
People smuggling
The facilitation of illegal border crossing for financial gain. Smugglers charge migrants fees to organise travel and entry into the UK. It is a crime against the state, not the migrant. The relationship between smuggler and migrant typically ends on arrival. Organised crime groups — including Kurdish, West Balkan, and Sudanese networks — are heavily involved in Channel crossings.
Human trafficking
The recruitment, transportation, or harbouring of people through coercion, deception, or force for the purpose of exploitation — including forced labour, sexual exploitation, domestic servitude, or organ removal. Unlike people smuggling, trafficking is a crime against the individual victim. Human trafficking is a form of modern slavery and does not require a border crossing.
Visa overstay
Remaining in the UK beyond the expiry of a visa or leave to remain. Overstaying is a criminal offence. It is one of the most common routes into irregular status and is difficult to quantify, as the UK lacks a reliable system for matching departures to entry records. The government does not publish estimates of the total overstayer population.
Border Security Command
A unit established in 2024 to coordinate the UK’s response to organised immigration crime, reporting directly to the Home Secretary. It directs the National Crime Agency, police, and intelligence agencies to dismantle people smuggling networks. It was backed by £75 million and given counter-terrorism-style powers under the Border Security, Asylum and Immigration Act.
One-in-one-out returns scheme
A bilateral pilot arrangement between the UK and France, in force from August 2025, under which the UK returns a number of small boat arrivals to France in exchange for accepting an equivalent number of asylum seekers via an official route. Around 300 people were returned under the scheme in its first months. It is intended to undermine the smuggling business model, though critics question its scale and deterrent effect.
Detected arrivals
People identified by the Home Office as arriving in the UK without authorisation, either at the border or within 72 hours of entry. Small boat arrivals are the most visible category because most present themselves to authorities on landing. Clandestine entries via lorries or ferries are less reliably detected and therefore underrepresented in official statistics.
Border Force
The law enforcement command within the Home Office responsible for securing the UK’s borders at ports and airports. It checks all passengers and freight entering the country, enforces immigration and customs laws, and intercepts small boats in the Channel. Around 10,000 people work for Border Force across its regional operations.