Detectives have arrested seven people, including a solicitor and a property developer, as part of a major inquiry into large-scale money laundering allegations.
A Metropolitan Police spokesman said the suspects, believed to have links to a high-profile organised crime gang, were detained in coordinated raids in London, Kent, Surrey and East Sussex at about 6.30am today.
The four men and three women, including a trained accountant-turned-property developer, are suspected of involvement in laundering large sums of cash through an investment scheme.
The Met said around 50 officers, including dog-handlers and specialist financial investigators, executed search warrants at residential addresses in Limehouse, Shoreditch, Hendon, Finchley, Dartford, Dorking and Camber Sands, near Rye.
During the raids under the codename Operation Octopod, an order under the Proceeds of Crime Act was served on an accountant's office.
Approximately £100,000 in cash was seized at a property in Shoreditch and detectives have also recovered financial documents, computers and mobile phones as part of the investigation.
The officer said: "The group as a whole is known to be involved in serious and violent crime which is harming people and damaging communities across London.
"Operation Octopod is a demonstration of the sheer investigative force the Met can apply to organised gangs, some of whom think they can hide criminal cash from the police."