Watch: GCHQ director speaks on cyber challenges facing UK after Ministry of Defence hack

Watch as GCHQ director Anne Keast-Butler gives a keynote address at a cyber conference in Birmingham on Tuesday, 14 May.

It comes after a cyber attack on the Ministry of Defence (MoD).

It has been speculated that China carried out the hack, but Rishi Sunak has declined to identify the “malign actor” behind it.

A third-party payroll system was hacked, potentially compromising bank details of service personnel and veterans, the government confirmed.

A very small number of addresses may also have been accessed, officials added.

The prime minister previously said there were “indications that a malign actor” had compromised the database, but would not attribute the attack to a specific state or “actor”.

David Cameron has said the safety of the nation will be a key choice for voters at the general election.

The foreign secretary said “security will be on the ballot paper” when Mr Sunak calls the election later this year.

Lord Cameron said the Conservatives' commitment to spend 2.5% of gross domestic product on defence by 2030 was in stark contrast to Labour’s “bunch of people who’ve got no plan”.