The number of immigration arrests on UK construction premises during the first nine months of 2025 was almost three times the 2024 figure and the highest for at least a decade.
Data supplied to Construction News under the Freedom of Information Act showed that from January to September there were 206 immigration enforcement visits at construction premises, with 477 people arrested.
The total rocketed from just 167 arrests from 119 raids in all of 2024, with both figures for the first three quarters of 2025 higher than any yearly total since 2016, the earliest year for which Construction News has been supplied with data.
Updated figures provided to CN this month showed that in 2023 there were 218 arrests made during 142 visits.
Last year, the department said that, since 2016, the number of arrests previously peaked at 408, from 323 raids in 2019.
A Home Office spokesperson said: “Illegal working undermines honest employers, undercuts local wages and fuels organised immigration crime – the British public will not stand for it, and neither will this government.”
He said enforcement action is at the highest level in British history and, across all sectors, illegal working arrests have risen by 63 per cent since the current government came to power.
“The home secretary has announced the most sweeping reforms to tackle illegal migration in modern times and will make Britain a less attractive destination for illegal migrants and will make it easier to remove and deport them,” he added.
The Home Office figures did not indicate whether the arrest figures it provided related to employers, employees, gangmasters or others.
However, data obtained by CN also showed that 74 civil penalties were issued to construction companies over immigration offences up to the end of October this year, with a combined value of £4.9m.
This was up from 57 penalties during the whole of 2024, which were valued at £2.5m. Just 16 civil penalties were handed out in 2023.
Employers see their fines reduced by 30 per cent if they pay within 21 days.
Lauren Saunders, deputy director of frontline services at Unseen, a charity that works to tackle modern slavery, said that the rise in arrests would be positive if they were of employers exploiting workers.
She said: “The focus should be making sure that those industries and those firms follow the right employment regulations, that there are visa checks happening for all individuals working within the supply chain, and that there’s methods for checking on worker wellbeing, such as whistleblowing processes, so that individuals who aren’t being treated as they should be are able to come forward.”
Tamana Aziz, director of business immigration law at Duncan Lewis Solicitors, said the figures show the need for construction companies to be meticulous in how they employ migrant workers, and that failing to take care could lead to business disruption, project delays and reputational damage, as well as the arrests and fines.
“Employers must conduct right to work checks correctly and consistently, and ensure that documentary evidence is retained securely.
“It is vital to verify that any subcontractors or labour suppliers used are also fully compliant, as liability can extend beyond direct employees. Employers should also maintain ongoing monitoring procedures, particularly where staff move between projects or roles.”
She added: “With enforcement at its highest level in a decade, now is the time for firms to review their policies, train staff, and seek legal guidance to ensure full compliance.”