Western economists have estimated that before the war Hamas was bringing “at least” $1 billion a year into Gaza - similar to the national budget of Somalia, a country with a population that is seven times bigger.

Of that revenue, around half – $500 million a year – was being made from the terror group’s investment and business portfolio.

“There are financiers working for Hamas all over the Middle East, in Algeria, UAE, Kuwait, some investing in shopping malls, some in mines,” business editor Rachana Shanbhogue told an Economist podcast last week.

“It seems that some of them may employ Hamas members and pay the money through salaries, some might donate money to Hamas linked charities, some Western officials think profits are being handed directly to Hamas,” she said.

According to US and Israeli estimates, she said, $360m of Hamas’s $1 billion annual income has come from taxes on goods brought into Gaza; £100m a year from Iran; and another approximately £50m from Qatar.

“The bulk of Hamas’ funds are out of the West’s reach. America has announced three rounds of sanctions on firms and people associated with Hamas since October 7 and most of those are aimed at stopping cash being transferred to Gaza.

“But there are lots of ways Hamas can circumvent these sanctions. The group uses crypto markets to shift millions of dollars; it’s constantly changing the names of old companies and registering new ones. This means that the target for officials is constantly moving.

What makes Hamas’s transactions particularly difficult for Western officials to reach, she said, was that “its financiers deliberately aim to dodge the dollar wherever they can”.

Aman, the capital of Jordan, used to be the main hub for Hamas financiers but “the government got too strict, it got closer to America” and now “more or less all of them live in Turkey, which is more accommodating”.

America claims that Hamas’s chief financier lives and works out of Istanbul, she said. Hamas have an office in the country, some of its officials have Turkish passports and even tacit approval from the Turkish state, she said. Companies which America says Hamas runs have won contacts to do official business in Turkey.

“This means it’s easier for Hamas bankers to move the money around. The Turkish banking system is hugely sophisticated which allows Hamas to carry out transactions around the world while avoiding sanctions,” said Shanbhogue.