The findings of a year-long undercover investigation into a violent migrant-smuggling gang were published by BBC News on 5 August - and, as a result, one person has now been arrested in Birmingham.
Here, one of our reporters who assumed a false identity and posed as a migrant, describes how he met one of the gang's senior members in a secret forest hideout.
I am walking towards the forest near Dunkirk, thinking about the battery in my pocket. I've hidden the wires under two T-shirts, but is anything still showing? Is my secret camera working? Is it pointing at the right angle? I have, at most, three hours of battery life left, and I need to get to the smuggler's secret camp, meet him, and get out safely.
This is perhaps the most dangerous and most important moment for me, the culmination of many months working on this investigation with the team.
There is a small team of high-risk advisors watching my back. With gang members monitoring everyone who enters the forest, I worry my advisors may end up exposing me rather than protecting me. But they play it perfectly and keep a low profile.
