In May this year, Royal Assent was given to the Immigration Act 2014. The government is getting tougher on illegal immigration and part of this legislation uses landlords to do so.
From October, if you rent a property or room in your house, you must ensure that the tenants have the right to reside in the UK, failure to do so could result in a penalty of £1,000 per adult residing in your property. If you are a letting agent, the price is bumped up to £3,000 per adult. The good news as far as I can see is that children are free!