Salah Abdeslam capture offers intelligence goldmine but important lessons must be learned

There’s a triumphant feeling here in Brussels tonight. Prosecutors, politicians and police officers are declaring the capture of Salah Abdeslam as a great victory in the fight against so-called Islamic State.

No wonder. In catching Europe’s most wanted man alive, the Belgian police have unearthed a potential goldmine - if they can get their suspect to co-operate.

Abdeslam was formally charged today with plotting a terrorist attack. Although he is said to be co-operating with police interrogators, he is reported to be resisting attempts to extradite him to France.

The Belgians might be tempted to keep him in Brussels for as long as they can, but the assumption here is that he will eventually be returned to Paris to stand trial in the city where he is accused of helping carry out last year’s atrocities.

This case may be about to deliver to authorities across Europe an unprecedented wealth of intelligence. It should have already taught them a long list of lessons too.

It would be an extraordinary trial. Under the glare of the French judicial system, the truth about IS's most ambitious plot, and the network behind it, may be revealed: from Raqqa, to Molenbeek, to Paris. And perhaps most valuable of all, he may be able to reveal what future ambitions IS has for bloodshed in Europe.

So the Belgians are right to have declared Friday a day of extraordinary success.

But let’s not forgot the preceding days of failure - all 126 of them. The inability of the authorities in Belgium to locate their targets, despite opportunity; let’s not forget that their prime suspect turned up a few yards from the very spot where security services and police officers started looking four months beforehand; let’s not forget the likely failures in international intelligence sharing that came before the November attacks in Paris.