The Foreign Office should have intervened to stop Mandelson’s deeply flawed appointment | Richard Dearlove

If Olly Robbins stood firm the government could have avoided this disastrous episode of bad political judgment that could cost the PM his job

• Richard Dearlove is the former head of the British Secret Intelligence Service

The restricted compartments of the UK’s national security infrastructure are clearly defined and closely controlled. To work across them requires “a developed vetting certificate”. The primary qualification for holding a “DV” is integrity, honesty and transparency in one’s personal and professional life. To lie about or hide potential vulnerabilities is an immediate disqualification. Staff who do not meet the DV requirements for whatever reason are barred from positions that demand DV clearance. There are no grey areas or soft edges.

The role of British ambassador in Washington is one of those posts. It sits across a number of highly classified compartments. It is no ordinary diplomatic job. The extensive security acreage of the special relationship includes, for example, the UK’s nuclear deterrent, the intelligence relationship, the UK-US alliance which ties together the National Security Agency and GCHQ by treaty, and other domains of great sensitivity. The ambassador has access to these even though their need to become involved in them in normal times is limited. The British staff that comes under the ambassador’s authority is extensive and stretches beyond those working in the embassy. The ambassador’s access to the US administration is also usually highly privileged, such is the nature of the special relationship.

Richard Dearlove is the former head of the British Secret Intelligence Service