Germany's former top intelligence official, August Hanning, has been arrested on charges including attempted treason and espionage, with Britain's MI6 fearing he leaked UK secrets, according to the Daily Mail. The report said secret services across the West were shaken by the news.

An arrest at this level is rare and implicates the trust binding Berlin's and London's intelligence services — and, by extension, the wider alliance that relies on both.

Hypothesis: the case fits a pattern of Russian-linked penetration of Western intelligence services that has recurred in Germany. Supporting this: the severity of the charges — treason and espionage against a former service chief — mirrors past Moscow-linked cases. Against this: the Daily Mail report names no foreign state and does not say who, if anyone, received the alleged leaks, so any Russia link is unconfirmed.

Unconfirmed so far: what British material was allegedly compromised, whether formal charges will follow the arrest, and who — if anyone — is accused of receiving it.

What to watch next: whether German prosecutors issue a formal indictment naming a receiving state, and whether London reviews its intelligence-sharing posture with Berlin as a result.