(This article was updated on 10 August to include a statement from the government.)

The Register of Overseas Entities that came into force on 1 August has 27 entries, as the government reminded foreign companies that own or lease property or land in the UK to register their beneficial owners by 31 January.

The government says registering with Companies House will ensure criminals cannot hide behind secretive chains of shell companies and will, in particular, support efforts to expose Russian oligarchs and kleptocrats using UK land to hide illicit wealth. The move has been pushed up the political agenda by Russia's war in Ukraine after years of promises.

At the time of publication, 27 company entities are registered, including those based in Jersey, the Bahamas, Canada, Hong Kong, the British Virgin Islands, Gibraltar and Isle of Man. Companies registered include Monument Real Estate, Fenwick 55, Shaftesbury Holdings, PMB Properties Holdings, Zealous Investments Holdings and Bez.

The information does not confirm the real estate owned or the exact shareholding of individuals but does report individual owners.

The government advised that overseas entities that already own land have six months to register. There are legal obligations on overseas entities to do certain things before they register and it is clear many will be undertaking those actions now before they seek to do so, it added.

The National Crime Agency believes as much as £100 billion a year is channelled through the UK via illicit financing but there are plenty of experts and politicians lining up to say it will have little to no impact.

The register requires anonymous foreign companies owning or seeking to buy UK land to reveal their true owners. The details of the entity and its beneficial owners are then available to the public.

Failure to comply with the Act could lead to a fine of up to £2,500 per day or a prison sentence of up to five years, as well as restrictions when buying, selling, transferring, leasing or charging property or land in the UK.

So what will it really mean for UK real estate and the often-private individuals who own so much of it?

The government is advising entities to use a UK-regulated agent to register and file the information.

Gavin Vollans, a real estate partner at Katten UK, says it is clear that property owners should move at high speed to avoid complications, with the lending market already needing confirmation of registration before progressing financing.

"An overseas entity will now need to deal with the Companies House registration requirements on the basis it is needed to buy, sell, lease for more than seven years or charge property at the Land Registry. There is no way around this.

"The key is to deal with the registration early enough in order to prevent any delays in such dealings with property. Without such registration ID in place, it will prevent registration at the Land Registry which in turn will prevent legal title from passing; lenders are likely not to fund until such Companies House registration has been dealt with since their security cannot be registered unless that has been done. Attending to this in a timely manner will be paramount.”

The British Property Federation's director of policy, finance, Ion Fletcher, says the body supports greater transparency around UK property ownership and as such welcomes the government moving swiftly to put the register in place.

But Fletcher downplays its ultimate impact. "It won’t be a radical change for the property sector, but we would expect that the new register would have a dissuasive effect on those who were intending to buy UK property with illicit funds.”

RICS has strongly supported the Economic Crime (Transparency and Enforcement) Bill and its efforts to combat money-laundering and corruption. It says the register can play a crucial role here, but says there needs to be clarity and improvements in three key areas.

There needs to be more transparency about which entities are covered by as a wide array of structures are used to own UK property. "Property professionals and their clients will need clear information to be able to determine with certainty whether an entity is in scope or out of scope of the legislation," it says.

It also wants to see proper verification of the information on the register to close potential loopholes.

"We would urge the government to ensure that Companies House, and also the Land Registry, have the resources they need in order to carry out any registration responsibilities effectively and efficiently, so that the Act does not result in unnecessary delays to UK property market transactions."

It also says it is clear professionals will be obliged to monitor and maintain the accuracy of the register and so warns there needs to be clarity on where responsibility lies, "given the different roles and access to information will be important in supporting effective oversight and enforcement without imposing unnecessary regulatory burdens".

A major potential loophole may render its ultimate goals unobtainable, as a property-owning company need only disclose its own beneficial owners and not the ultimate owner of the land.

John Cullinane, the director of public policy at the Chartered Institute of Taxation, the leading body representing tax accountants, told The Guardian said this would allow oligarchs to exploit the rules by holding property or land in the name of a nominee company, or by sharing the ownership with more than four relatives or friends.

The Labour MP Margaret Hodge, a long-term campaigner for a government crackdown on secretive overseas property owners, described the move as “more lead balloon” than the “silver bullet we were promised would stop abuses like money laundering in our real estate sector”.

She said the register is "riddled with flaws and loopholes that mean oligarchs and organised criminals will still be able to evade scrutiny and secretly purchase premium London property, such as Highgate mansions or Kensington townhouses".

Hodge wants the government to urgently put in place an open register of the true owners of UK land and property, not just those owned by companies.

In a statement to CoStar News, responding to some of the concerns about the register, a Department for Business, Energy and Industrial Strategy spokesperson said: "The Register intentionally focuses on identifying the true owners of overseas entities holding land in the UK by requiring the registration of the beneficial owners, and those that don’t comply face hefty fines or up to five years in prison.”

They pointed out that the Act already provides robust provisions to ensure overseas entities provide information about beneficiaries of trusts where there is a trustee who is a registrable beneficial owner, and said guidance for the real estate and other sectors about the requirements, including verification, can be found at: Read Companies House guidance on the Register of Overseas Entities