MI5 has apologised for failing to promptly disclose information to a woman who was attacked with a machete by one of its agents.

The woman, known by the alias Beth, has complained to the watchdog which considers complaints against the intelligence services.

In 2022 a BBC investigation revealed the man - who cannot be named for legal reasons - had used his role to coercively control Beth, his ex-partner.

He was physically and sexually abusive, and was filmed threatening to kill her and then attacking her with a machete.

Two years ago, the government took the BBC to court to block the story being broadcast.

It failed to do so, but succeeded in gaining him legal anonymity, having argued that the man - a right-wing extremist known publicly as X - would be in danger if publicly named. The BBC argued he should be identified so that women could be warned about such a predatory and violent man.