Just like most people who holiday in this part of Wales, the campers are British citizens; they live in the UK and they use British bank accounts. So, what is it exactly about people who come to Wilson’s farm that is different from the campers at other farms?

The uncomfortable reality is that, unlike most campers in this part of the world, the community leader and her friends are Black and Muslim. And people who are Black and Muslim are some of the primary victims of a system that was set up after the attacks of 11 September 2001 to stop terrorists from moving their money around. It’s a system that has failed to achieve its primary aim – terrorists are every bit as widespread now as they were two decades ago – while making life much harder for millions of innocent people.

After 9/11, officials wanted access to every tool that might help them save lives, and they thought tracing financial movements could be one of them. Within days, the UN security council demanded that all countries establish a system for freezing terrorists’ assets. In October 2001, the US president, George W Bush, signed the USA Patriot Act, which expanded anti-money-laundering rules to cover terrorists. That same month, the Financial Action Task Force (FATF), an inter-governmental body established in 1989 to craft a global approach to money laundering, published recommendations for a “basic framework to detect, prevent and suppress the financing of terrorism and terrorist acts”.

The FATF had been created at the height of the “war on drugs” to stop criminals hiding their earnings. The organisation spent the 1990s persuading, bullying and cajoling every country in the world into adopting common standards on regulating the financial system. Its primary weapon was to demand that professionals report suspicious transactions to the authorities, thus allowing governments to stop dirty money at source, with large fines and criminal prosecution for non-compliance.

On one level, since the FATF was the place that knew about dodgy money, it made sense to deploy its expertise against terrorist financing too. On another level, it made no sense at all. Money launderers take large volumes of dirty money and wash it through the financial system to make it look clean; terrorists take small amounts of clean money and – by using it to fund violence – turn it dirty. Why should mechanisms designed to catch one be able to pick up on the other?

And there was another problem: terrorists’ money only becomes criminal after they’ve committed their atrocities. For banks to be able to block it preemptively, they needed to have an insight into something they couldn’t possibly know: their customers’ future plans. Without that knowledge, they’d have no idea what they were looking for. Richard Gordon, a lawyer who worked for the International Monetary Fund at the time, says he tried to warn participants that they were acting too hastily. “To say that banks have to figure out on their own what’s terrorism finance, that’s lunacy, and I said that too. Didn’t matter, I was overruled,” he told me.