Three men aged 44, 45, and 48 were arrested in west and central London on Thursday on suspicion of assisting a Russian intelligence service, part of an ongoing national security investigation.

They were detained under section 3 of the National Security Act, and searches continued at multiple locations in west London.

While their nationalities were not disclosed, police said they were suspected of acting as surrogates for a Russian intelligence service, The Guardian has reported.

The head of London counter-terrorism policing warned that anyone approached to act on behalf of a foreign state in the UK could face serious legal consequences.