Mark Hollingsworth,

In the countryside around Tunbridge Wells, on the border between Kent and East Sussex, is a castle that few passersby would know is owned by Russia.

Seacox Heath, a grade II listed 19th-century castle, is rumoured to be used by Russian diplomats and FSB spies as a weekend and holiday retreat.

It is one of 18 properties in England owned by the Russian state that a Timesinvestigation has found could be seized and given to Ukraine.

Liz Truss, the foreign secretary, said this week that she was considering seizing frozen assets owned by Russians in the UK and redistributing them to victims of Putin’s war in Ukraine.

The Times can reveal that Ukraine is also considering legal action to take possession of the 18 properties, which could be worth up to £100 million. Many are clustered near Highgate, north London. The neighbourhood is popular with Russian diplomats and oligarchs who own some of the most expensive properties, now mostly frozen.

These include Witanhurst, London’s second largest home after Buckingham Palace, which is valued at £300 million and owned by the sanctioned billionaire Andrey Guryev. Russia also owns a luxury apartment block in Kensington, three houses on Holland Park and the castle in East Sussex.

Vadym Prystaiko, the Ukrainian ambassador to the UK, is hiring a lawyer to bring Russia to court. He hopes a British court would confiscate the properties or force Russia to sell them and share part of the profits. He said he would urge all Ukrainian embassies around the world to do the same, in a move that could result in a claim for properties worth billions. The money raised would be used for the war effort and the reconstruction of Ukraine once the war is over, the ambassador added.

Prystaiko added that despite the end of the USSR 31 years ago, “the issue of the equal distribution of the property of the former USSR remains unresolved”.

He said: “We appreciate Britain and the EU said they would help us rebuild Ukraine but it’s Russia that needs to pay for that … For us, this would be a straightforward way of doing it.”

In 1999 Ukraine challenged the Russian ownership of the properties, due to its former status as a founding member of the USSR. Ukraine was the only one of the 15 former Soviet republics to bring such a claim; others are said to have struck individual deals with Russia.

Documents from the Land Registry show that Volodymyr Vasylenko, then the ambassador to the UK, filed applications to prove to the UK government that Ukraine had a “beneficial interest” in the properties, in light of bilateral agreements between the country and Russia after the dissolution of the USSR. A Land Registry spokesman said that for such a charge to be registered, Ukraine had to prove its claim.

“Ukraine has a beneficial interest in all of the properties owned by the former USSR in the United Kingdom,” the charges filed with the Land Registry read.

Such charges, known as caution against dealings, were scrapped in 2002 but existing charges continue to have effect.

The charges are still standing and there is no record that Russia has ever opposed them.

John Sandweg, a former general counsel of the US Department for Homeland Security, said: “Documents demonstrate that after the collapse of the Soviet Union the Russian Federation took possession of an extensive array of properties around the world, ignoring Ukraine’s ownership stake.

“The Russians simply stole hundreds of millions in real estate. The continued possession of those properties is now contributing to their terrorism of the Ukrainian people.”

Only two of the 18 properties are listed as diplomatic premises by the Foreign Office, which regularly publishes an updated list of foreign missions in the UK. They are the Russian defence attaché’s office and the trade delegation of Russia in the UK at 32-33 Highgate West Hill.

It is believed Russia could claim diplomatic immunity over properties in case Ukraine tries to enforce its interest.

Seacox Heath, one of the largest properties, is thought to be worth millions of pounds and boasts mock-Gothic turrets, chiselled balconies and terraced lawns on its 30 acres of grounds. The estate includes two detached cottages, tennis courts and a football pitch.

Seacox Heath

Seacox Heath

During the cold war KGB officers were observed burning shredded secret files on a bonfire in the house’s garden.

“We once sneaked into the back garden and kicked over the ashes for a disappointing reward: the only thing readable was a list of items on a BBC news broadcast,” John Miller, the Moscow-based foreign correspondent who died last year, wrote in his memoir.

The ‘dacha’ used to be the Russian ambassador’s country residence in the 1990s but it is unclear what the house’s official function is today.

Built in a French-chateau style in 1871, the existing structure belonged to the second Viscount of Goschen. He gave it to the Soviet Union in 1947, allegedly as a gift after Russian sailors saved his son during the war. The estate was previously used as the refuge of the leader of the 18th century Hawkhurst gang, Arthur Gray, and allowed the smugglers to lead raids across the coast of Dorset.

In 1999, the property was at the centre of a row with a local sheep farmer, who accused the Russian embassy of letting loose a pack of Alsatians that killed 50 ewes. An embassy spokesman said at the time: “The estate is our property and everything there is covered by diplomatic immunity according to the international convention so yes, the dogs have immunity, but the dogs are not diplomats.”

Earlier this year, locals staged a protest by placing Ukraine flags in front of the house.

The Foreign Office declined to comment.

The Russian Embassy in the UK said: “Russia, as the sole continuator state of the former Soviet Union, has assumed rights to all Soviet properties abroad and, unlike Ukraine, has repaid all Soviet debts.

“Ukraine’s claims have no basis in international law. Besides, diplomatic premises and homes of embassy staff are protected by diplomatic immunity. We assume the UK is loyal to its obligations under the Vienna Convention on Diplomatic Relations, just like Russia is abiding by them with regards to the British Embassy in Moscow.”

This article was updated on July 11, 2022, to include a comment from the Russian Embassy, which had been omitted in error