Robert Hannigan, who ran the UK’s signals intelligence agency for three years, revealed that Pyongyang is “after our money”.
He also claimed that the reclusive regime is attempting to improve its hacking abilities by collaborating with Iran and criminal networks operating from southeast Asia and China.
In his first newspaper interview since leaving his role, Mr Hannigan said: “Their missiles are not going to reach the UK but their cyber-attacks did reach the NHS and other parts of Europe.
“As sanctions bite further and North Korea becomes more desperate for foreign currency, they will get more aggressive and continue to come after the finance sector. They are after our money.”