Labour has urged the Conservatives to hand back a £5m donation from the party’s senior treasurer, Mohamed Mansour, as it questioned why it had taken so long for one of his companies to wind down its business in Russia. In a letter to the Tories, Labour’s chair, Anneliese Dodds, called on the party to justify donations of almost £7.5m that she said had come from people and firms who had had links to business in Russia. Labour renewed its attack on the Conservatives over donations after the Tories criticised its acceptance of £1.5m from Dale Vince, the founder of the energy company Ecotricity who also funds the campaign group Just Stop Oil. Labour drew particular attention to Mansour’s co-ownership of Mantrac, which earlier this week still appeared to have a Russian-language website advertising its services as an authorised dealer of Caterpillar hardware and equipment, with 14 offices in the country. Mantrac said in May that it was winding down its business in Russia, more than a year after Moscow’s invasion of Ukraine drew international condemnation and calls from Rishi Sunak and Boris Johnson for businesses to withdraw. The website was taken down on Wednesday, and it is understood Mantrac’s operations in the country were fully suspended in May. Dodds said it had been brought to her attention that “the Conservative party senior treasurer Mohamed Mansour’s firm is operating a Russian-language website” and questioned his previous financial ties to Russia “at a time when the UK is rightly imposing sanctions on the Putin regime and the prime minister has repeatedly called on British companies to pull out of Russia in order to ‘inflict maximum economic pain’ on Putin’s regime”. Mansour revealed last month that he was giving £5m to the Conservatives, the largest donation to the party since Sir Paul Getty in 2001. Mantrac said it was winding down its business in Russia at about the same time. In her letter, Dodds said the Conservative chair, Greg Hands, should “get a grip” on the flow of donations from people with links to Russia. She said public confidence in politics and politicians depended on parties “doing the right thing” and she urged him to explain what due diligence had been done on Mansour’s donation. She wrote: “Rishi Sunak promised a government of professionalism, integrity and accountability. It’s time to put his money where his mouth is. At a time when public confidence in politicians has been damaged by Conservative scandal after Conservative scandal, it is vitally important that the party comes clean on these donations and returns them in full.” Labour has also renewed calls for the Conservatives to give more than £2m in donations they have received since 2007 to charity because they came from the wife of a former deputy finance minister in Vladimir Putin’s Russia. Lubov Chernukhin has also been a member of the Tories’ leaders group of top donors who give at least £50,000 a year to the party, and a member of the party’s advisory board of super-rich donors. A spokesperson for the Chernukhins said: “Neither Lubov nor her husband, Vladimir Chernukhin, support, or have ever supported, the policies of Putin. Mr Chernukhin was appointed as deputy minister of finance by prime minister Mikhail Kasyanov and formed part of his government for two years. “Mr Kasyanov was dismissed by President Putin in 2004 due to significant disagreements on policy. He has since become one of the leading critics of President Putin and an opposition leader. Shortly after Mr Kasyanov’s firing, Mr Chernukhin was dismissed and subsequently had to leave the country. In the 19 years since, he has never returned to Russia. “As a British citizen, Mrs Chernukhin is entitled to make donations to political parties based on her personal wealth as she sees fit; any suggestion to the contrary is patently xenophobic. Her donations to the Conservative party have been declared in accordance with the rules of the Electoral Commission.” A Conservative party source said: “This is rich coming from Dodds who sat next to Corbyn as he slagged off British intelligence when a chemical weapons attack took place on British soil. “Labour are clearly rattled by the exposing of their shadowy relationships with eco-zealots. They are so deep into the pockets of Just Stop Oil that they have the criminal group writing their energy policy for them.” The Conservatives have been approached for comment.