Isil terrorists are plotting to carry out biological and nuclear attacks on Britain and Europe, EU and Nato security chiefs have warned.

There is a “justified concern” that Islamist fanatics in Syria and Iraq are trying to obtain substances of mass destruction such as biological, chemical and radiological weapons.

The terror group is also trying to develop new ways of avoiding security measures to carry out attacks such as bombs implanted in human bodies and hacking driverless cars, an international security conference in London heard.