Oligarchs using UK property to launder illegal wealth are being targeted by a new register which has come into force.
Any anonymous foreign company seeking to buy UK land or property will need to reveal the true owners.
Foreign companies that refuse to disclose their true owner could face fines of up to £2,500 per day or up to five years in prison.
The register comes amid economic sanctions in response to the Russian invasion of Ukraine.
Foreign organisations who already own land in the UK will have a six month period to register their beneficial owners or managing officers.
Business Minister Lord Callanan said: "We have been clear that the UK is a place for legitimate business only, and to ensure we are free of corrupt elites with suspicious wealth, we need to know who owns what.
"By getting this first of its kind register up and running at breakneck speed, we are lifting the curtain and cracking down on those criminals attempting to hide their illicitly obtained wealth."
The register was part of the Economic Crime (Transparency and Enforcement) Bill in February 2022, in response to Russia's invasion of Ukraine.
The bill proposes that anyone setting up, running, owning or controlling a company in the UK to verify their identity with Companies House, a government agency, as well as giving Companies House the power to challenge suspicious information.
The register applies to property bought since January 1999 in England and Wales, and since December 2014 in Scotland.
Labour MP Margaret Hodge said the government needed to go further to tackle money laundering.
"To truly stop the flows of corrupt wealth into our housing market, the government must urgently put in place an open register of the true owners of UK land and property, not just of those owned by companies," she said.
"Anything less would demonstrate once and for all that this government is truly soft on dirty money."
Any overseas body that has disposed of property since 28 February 2022 - when the legislation for the register was first announced - will be required to provide a statement to Companies House.
Multi-million pound country manors in the south of England and luxury flats in London's most expensive areas are among the homes which have been linked to Vladimir Putin's regime and associates.