Spanish police hunting for the driver of the van used in the Barcelona attack are focusing their efforts on a 22-year-old Moroccan national.

Younes Abouyaaqoub is said to be at the centre of the investigation into the massacre on Las Ramblas, and police believe he may still be alive and at large.

Meanwhile, a different suspect wanted in connection with the terror attacks has been killed, according to police sources.

17-year-old Moussa Oukabir rented the van which ploughed into pedestrians in Barcelona on Thursday afternoon. It is believed he was one of the five men killed during the second attack in the town of Cambrils. 

There are now calls for barriers to be introduced in the Las Ramblas area - where it happened.

But international security and terrorism expert Dr Martin Coward says this isn't always the answer: