A project manager from the UK’s BP who survived the In Amenas terror attack in Algeria has told a British court it was “an inside job”.

The In Amenas gas plant in eastern Algeria is operated by BP, Norway’s Statoil and Algeria’s state-owned energy company Sonatrach, and was overrun by Al-Qaeda-linked terrorists in January 2013, in an attack that saw more than 60 people killed.

In a statement to an inquest into the attack, the BP employee, Nick Hitch, said the attackers had deliberately targeted senior officials and the militants “clearly had had help from people inside the facility”.

“I formed the view there was effectively an Al-Qaeda cell in the camp,” he told the inquest at the Royal Courts of Justice on 7 October. “They showed a lot of inside knowledge in the way they took out the facilities.”

A total of more than 800 people were held hostage at the plant during the attack.

The inquest is due to continue on 8 October.

In early September, Statoil announced that normal operations were being resumed at the facility, 19 months after the attack. Since the hostage crisis, the firm had kept its permanent workers away from the gas field.

The return to normal operations came after the implementation of new security measures, including a new airport, observation helicopters and a permanent military presence on the site.