The three men are being prosecuted for having acted between August 14, 2024, and February 16 this year to "help a foreign intelligence service". According to the London police, it concerns Iran.
The men are said to be between 39 and 55 years old and were arrested in London earlier in May.
Dominic Murphy, from the police's counter-terrorism unit, says that the charges come after "a very complex and fast-paced investigation" and that the allegations are "extremely serious".
"Since the men were arrested, the investigators have worked around the clock and we have had close cooperation with our colleagues in the prosecution authority to get this far", says Murphy in a statement.
One of the men is being prosecuted for "surveillance, reconnaissance, and research using open sources" with the intention of "committing serious violence against a person in the UK", according to a statement from the police.
The other two are being prosecuted for the same crime, but with the intention that the violence would be "committed by others".
