“At the same time, we have also introduced strong measures through the Immigration Act to tackle illegal working, including making it easier to prosecute employers who repeatedly break the rules and creating the power to temporarily close businesses that do not comply with the law.”
The majority of the 97 people arrested were Vietnamese nationals, but the number also included suspected immigration offenders from Mongolia, Ghana, China, Nigeria, Pakistan and India.
Those who are potential victims of trafficking will be offered support, while those who have no right to be in the UK will be removed, the Home Office said.
Officers also issued notices to 68 businesses warning them they may be liable for financial penalties of up to £20,000 per illegal worker found if they cannot provide evidence that appropriate right to work document checks were carried out.
Fourteen people were referred to the National Referral Mechanism hub, which supports those identified as possible victims of slavery and human trafficking.
The operation also focused on the construction, care, cleaning, catering, taxi and car wash industries during 2016, with further activity in similar sectors planned for 2017.