The hon. Gentleman makes an interesting point, but as he will well know, one challenge that we have faced is understanding overstaying, which was why we introduced exit checks at the start of this year to identify more clearly patterns of behaviour, sectors and other elements that are relevant to those who are not overstaying the leave granted to this country. He asks me for information that is not currently held, and it is equally difficult to estimate the size of the population who are working illegally. I am sure that the labour market enforcement director will consider that when he examines the size of the problem in his reports to Ministers, but that does not undercut what immigration enforcement representatives say to me about the gap in the existing legal framework.
We need to ensure that there is an overarching approach on criminal law and, as I have said, there is a criminal aspect of people entering the country illegally. We are creating an additional offence for those who are overstaying, who are not covered by the existing criminal law. That means that they are not subject to proceeds of crime legislation, which is having the negative impact about which we have heard.
I share the concerns of the hon. and learned Member for Holborn and St Pancras about ensuring that an offence is used when circumstances suggest that it is the right approach. However, it is important to remember that individuals with an irregular immigration status will have committed a criminal offence under existing legislation by coming into the UK in the manner that I have described, regardless of whether they are working. Therefore, I do not accept arguments made about how the criminal law, or an extension to it in the form of the offence we are discussing, will make the situation more difficult, as has been suggested. However, there are some important points to which I want to respond, including what the hon. Member for Rotherham said about slavery and existing offences under the Modern Slavery Act 2015. She served on the Modern Slavery Public Bill Committee, so she understands these issues.