Three of them also face other charges after being found with multiple passports from different countries.

The three charged under the Identity Documents Act were named as:

• Orlin Roussev, 45, of Princes Road, Great Yarmouth
• Biser Dzambazov, 42, of High Road, Harrow
• Katrin Ivanova, 32, of High Road, Harrow

The five arrested are:

• A 45-year-old man in Norfolk
• A 42-year-old man in west London
• A 32-year-old woman in central London
• A 31-year-old man in west London
• A 29-year-old woman in north London

All were arrested in February.

Roussev, Dzambazov and Ivanova had 19 passports, driving licences, identity cards and residence permits from countries including the UK, France, Italy, Bulgaria, Spain, Greece, Croatia, the Czech Republic and Slovenia.

The three of them have been remanded in custody and will appear at the Old Bailey on a date still to be agreed.

The 31-year-old man and 29-year-old woman arrested have been released on bail until September.

Metropolitan Police's counter-terrorism command is leading the investigation.

A former British spy has told Sky News that producing multiple types of identification is "extremely helpful and useful... from a counterintelligence perspective".

Christopher Steele, who ran the Russia desk at MI6 in London between 2006 and 2009 and worked there in the 1990s, said: "I think it's early days yet to make any definitive judgements about what's behind this. Clearly, the government appears to believe that they were working for the Russian state, Russian intelligence."

He added: "It's an impressive operation. It will act as a deterrent, I think, for others.

"But of course Russia is effectively at war for the moment and Russia and Putin will stop at very little to pursue their state objectives, whether it's on the battlefield or in the sort of espionage elements of areas of the UK and Europe."