Ben Wallace
Ben Wallace said the high casualties in a chemical attack were ‘everybody’s worst fear’. Photograph: Rex/Shutterstock

Islamic State wants to carry out a mass casualty attack in Britain and has “no moral barrier” to using chemical weapons, a minister has said.

The security minister Ben Wallace said there were reports of Isis using chemical weapons in Syria and Iraq, where it controls large areas, and that Moroccan authorities had apprehended a cell in February which was harbouring substances that could be used to make either a bomb or a “deadly toxin”.

He also pointed to a recent Europol report that warned of the chemical threat and the potential realisation of “everybody’s worst fear”.

He told the Sunday Times that the group’s ambition was “definitely mass casualty attacks. They want to harm as many people as possible and terrorise as many people as possible.

“They have no moral objection to using chemical weapons against populations and if they could, they would in this country.

“The casualty figures which could be involved would be everybody’s worst fear.

“We have certainly seen reports of them using it in Syria and Iraq [and] we have certainly seen aspiration for it in Europe.”

Wallace also warned about the threat from terror groups, Russia and cyber-attackers trying to plant people in the government, the military and leading businesses.

“There are traitors. We have to be on our guard for the enemy within,” he said.

“The insider threat, as we would call it, is real and it can be exploited and there are people trying to do that as we speak.”

This comment comes after a year in which Europe suffered a spate of terror attacks using less sophisticated means.