The Foreign & Commonwealth Office website does not seem to provide details of any easy methods for the public to contact the FCO on anything except travel related matters.
There is a General telephone number,but no email, or postal address etc. or any email or postal mail contact details for the Foreign Office Ministers etc. They even seem to keep their Press Office details secret from the general public.
Hence we have reluctantly had to resort to a Freedom of Information Act request to try to elicit the names and job titles of the Russian and United Kingdom diplomats etc. who have been or who are in the process of being expelled as persona non grata, following the diplomatic incident over the failure to extradite or prosecute the suspect Andrei Lugovoi, in the radioactive Polonium 210 murder case of British citizen Alexander Litvinenko.
Every foreign government and intelligence agency will know who these people are, through their own normal diplomatic representatives in London and Moscow, so why shouldn't the UK general public know as well ?