On July 18 last year, at a holiday airport in the European Union, a man with a hidden bomb climbed aboard a bus full of tourists and blew himself up. Five holidaymakers were killed as well as the driver. It is fair to assume that whoever organised this attack saw it as a success, but would have been made even happier had the death toll been greater.

The airport was Burgas in Bulgaria; the tourists were Israelis. And, according to a report issued by the Bulgarian Government yesterday, the attack was carried out by members of the “military wing” of the Lebanese extremist party Hezbollah, using false Australian and Canadian passports.

There is in the West something of a debate on how to understand Hezbollah.