She was seen leaving the embassy yesterday through the back door where a blacked-out Honda car and a G4S security guard waited for her.

The former Conservative Party head of press was planned on travelling to the US as part of her job with an environmental group Oceana. But she is thought to have been barred because of her five day visit to Somaliland, which is suffering from a civil war and has no diplomatic relations with the US.

Her trip involved spending time with the country’s president Muse Bihi Abdi and they are believed to have discussed women’s issues and sea pollution. She went with her friend Nimco Ali, a campaigner against female genital mutilation, who was born in Somaliland, MailOnline reports.

Because Miss Symonds is not married to Johnson, it is unlikely Number 10 will intervene on her behalf. The UK is one of the few countries who do have diplomatic relations with Somaliland, which separated from Somalia in 1991.

But the US does not recognise the breakaway nation as an independent country.