Boris Johnson has pointed to a fear of running into a “brick wall of lawyers” when asked why the UK has not imposed sanctions on Roman Abramovich.
Labour has demanded action against the Chelsea Football Club owner after a leaked Home Office document flagged his “links to the Russian state and his public association with corrupt activities and practices”.
The prime minister had insisted he could not discuss individual cases, but opened up about Mr Abramovich in an interview with various European newspapers.
“None of us want to live in a country where the state can take your house off you without a very high burden of proof and due process,” he said.
“There’s no point saying, yeah, we’re going to go after him, and then you come up against the brick wall of lawyers. So we have to get it right. We’re also trying not to just make this about one individual.”
Ministers have also refused to address criticism that the decision not to impose sanctions on Mr Abramovich will allow him to take the proceeds from the sale of Chelsea out of the country.
Mr Abramovich, who became a billionaire from privatised oil assets following the collapse of the Soviet Union, has denied having close ties to Vladimir Putin, the Russian president.
His spokesperson has said he has not done anything that should lead to sanctions. The “net proceeds” from the sale of the football club will go to a charitable foundation to help “all victims of the war in Ukraine”.
The government has been criticised for lagging behind the EU and the US in imposing sanctions on Russian oligarchs with property and other assets in the UK.
New legislation will now be toughened to allow action to be taken automatically when sanctions have been imposed elsewhere and to limit human rights protections.
Foreign Office lawyers had conceded that it could otherwise take “months” to sanction other prominent oligarchs, triggering tensions with ministers.
And the government has backed down on allowing 18 months for foreign owners of UK properties to register those homes, cutting the proposed “grace period” to six months.
The move still falls far short of the 28 days demanded by Labour, which has warned “Putin’s cronies” will be able to “launder their money out of UK property market and into another safe haven”.
But Mr Johnson told the foreign reporters: “Top line of what our package on Monday will do is that the measures that you have against individual oligarchs in Europe will essentially allow us to catch them too.”
The prime minister also said there is “plainly more to be done with sanctioning some banks, with tightening Swift” – access to the international payments system.
“It feels to me as though Vladimir Putin – and it’s clear from what’s happening – has decided to double down,” he said.
“He sees no way out of the cul de sac that he’s in, except to continue with the destruction, the pulverising of innocent populations, in innocent European cities. So we will have to respond together with an intensified package.”