A Foreign Office minister has ruled out a prisoner swap for the imprisoned Russian opposition figure Vladimir Kara-Murza, a British citizen, who MPs have expressed concern about after the death of Alexei Navalny. Kara-Murza’s wife was now adamant that she wanted everything to be done to get her her husband out of Russia, said the Conservative backbencher Bob Seely, who urged the government to countenance swapping imprisoned spies for the pro-democracy activist who was now the most high-profile Russian political prisoner. Seely, who is in contact with the Kara-Murza and Navalny families, said when he had discussed prisoners swaps with the Foreign Office it had been made clear to him that such moves only encouraged state hostage taking. “His health is in a fragile condition and if Putin can kill Navalny he can kill Kara-Murza,” said the MP, who chairs the all party parliamentary group on Russia. He urged a Foreign Office minister to reassure parliament that “every conceivable course of action, potentially including negotiated swaps using Russian spies” will be looked at “because otherwise [Kara-Murza] will be next”. Leo Docherty, who was making a statement on the death of Navalny in the absence of the foreign secretary, David Cameron, said: “We could not and would not countenance a policy of prisoners swap but of course we continue to make every effort to support Mrs Kara-Murza and to seek the release of Vladimir.” Kara-Murza, who is serving a 25-year sentence for treason, has twice survived poisonings that he blamed on the Russian authorities, and rejected the charges against him as punishment for standing up to Putin. Docherty, the minister for Europe and North America, said earlier it was right to describe Navalny’s death as murder and told MPs that Britain continued to look at new legal paths to ensure that frozen Russian assets could be used help those affected by Russia’s invasion of Ukraine. Stephen Doughty, shadow minister for Europe, said that Navalny had not just challenged Russian kleptocracy and autocracy but also past western enablement of this and his campaign had been not just about Moscow but the role played by London as a haven for Russian oligarchs. “We must deliver the changes we campaigned for. The reality is that we still have much further to go,” he said, calling for the government to review further sanctions against Russia, including an assessment of the nearly 8,000 people on Navalny’s “list” of Vladimir Putin’s henchmen. “It was a source of shame that under successive Tory governments Britain became the money-laundering capital of the world and our tributes to Alexei Navalny must be more than just rhetorical.” Another Labour MP, Margaret Hodge, said a loophole in Britain’s sanctions regime means countries like China and India continued to import Russian crude oil, process it and then sell into the UK as a refined oil. About 5.2m barrels were imported last year, said Hodge, who added this resulted in £141m in tax revenue being channelled into the “Kremlin’s war chest”. Conservative backbenchers, meanwhile, pressed Docherty to dismiss Russia’s ambassador and sever diplomatic ties with Moscow. “What advantages remain in maintaining diplomatic relations with this murderous and barbarous regime?” asked Jacob Rees-Mogg. Docherty said that the benefits including being able to deliver “message of outrage and condemnation” and also to advocate for consular access to those held by Putin’s regime.