Revealed: the secret UK immigration dodges on offer on the high street. Theresa May has promised to stick to a promise to bring down net migration to the tens of thousands, and post the vote for Brexit, is under pressure to be tough on immigration. But File on 4 has found a market in fake documentation is helping some migrants who aren't eligible to come here, to get the necessary visas. High street immigration advisers, and even a solicitor tell the programme's undercover researcher how to buy their way in using fake documentation. The programme asks what the authorities are doing to catch the crooks. Reporter: Jane Deith Producer: Paul Grant Editor: Gail Champion.