Effective today, UK restrictions upon Romanian and Bulgarian passport holders entering the United Kingdom are lifted, meaning that their nationals can freely travel into the UK, for the purposes of employment. While some commentators worry that there will now be a flood of job-seekers from those countries, there is a more serious aspect of this new policy, which involves increased risk of financial crime in London, as the UK could be targeted by Russian organized crime.
Both Bulgaria and Romania offer passports to any foreign nationals who show family lineage in areas that was formerly part of their national territory. Romania, in particular, has been extremely flexible with applicants who show a connection with Moldova, which was a part of Romania until the Second World War. Russian and Ukrainian nationals who can show a family connection can easily obtain a Romanian passport.
Given that Russian organized crime members abused Israel's Law of Return, by fabricating Jewish ancestry to obtain Israeli passports in the past, you can expect them to repeat this activity with Romanian, and possibly also Bulgarian, passports. Furthermore, the Bulgarian language uses the Cyrillic alphabet, which was created there, further facilitating the ability of Russian criminals to pose as Bulgarians.
If I was a money launderer, working for a Russian organized crime group, and wanted to expand my operations into the EU, I would find a way to obtain, or counterfeit, evidence of Romanian ancestry, through Moldova, and move myself, and part of my operation, into the City, London's financial district. Please govern yourself accordingly.