The Ukrainian connection: John Whittingdale amongst MPs criticised for close ties with ex-Ukrainian President Victor Yanukovych's favourite energy magnate Dmitry Firtash

Senior British politicians have been challenged over their links to a billionaire businessman who was one of Ukraine’s most powerful figures under the country’s deposed President Viktor Yanukovych.

The energy magnate Dmitry Firtash has faced allegations of media censorship and prompted demonstrations in the City of London by British-based Ukrainians when he was allowed to open the London Stock Exchange in October after funding a “Days of Ukraine” cultural event alongside the Thames. This was run by his charity, the Firtash Foundation. British Ukrainians staged a demonstration outside its secretariat in Leeds at the start of the unrest in Kiev.

Mr Firtash has not been shy of his links to the ousted Ukrainian leader, with promotional material for the London event boasting: “The Days of Ukraine in the UK received support at the highest level, including the patronage of President Viktor Yanukovych.”

However, this has led to questions for the Conservative peer Lord Risby and John Whittingdale MP, chair of the House of Commons media select committee, who were among the members of the organising committee for Days of Ukraine and have other ties to the billionaire.

The event was launched in the Houses of Parliament and attended by the Speaker John Bercow and the Vice Prime Minister of Ukraine, Kostyantyn Gryshchenko. It was sponsored by the businessman’s Group DF global network of companies and the Foundation.

Mr Whittingdale is also director of the British Ukrainian Society (BUS), which the MP says has received financial support from Mr Firtash. In the register of members’ interests, Mr Whittingdale lists the society’s address as at a palatial office block in London’s Knightsbridge used in the past by the Firtash Foundation and Group DF.

The MP, who is chairman of the British-Ukraine All Party Parliamentary Group, has travelled to Ukraine at the BUS’s expense.

Mr Whittingdale went on a £2,800 trip to Kiev in 2010, “to meet members of the government of Ukraine and opposition”. He returned to Ukraine in 2011 as a guest of the society and in his capacity as chair of the British Ukraine All-Party Parliamentary group. That trip cost £1,700 and was to “meet members of the government of Ukraine”. A four-day visit in 2012 to attend a conference in Yalta, Ukraine cost £2,520. He visited the same conference for a £2,680 week-long trip in September last year.

In Parliament, the Labour MP Helen Goodman, the shadow Culture minister, challenged William Hague, the Foreign Secretary, over whether the Tories had taken money from supporters of the Yanukovych regime. Mr Hague described her suggestion as “ridiculous”.

Ms Goodman told The Independent: “It is vital that the British Foreign Secretary can negotiate in the knowledge that there are no conflicts of interest.”

Mr Whittingdale said his work sponsored by the BUS was intended “to promote closer relationships between Britain and Ukraine” and the society’s funding of his trips enabled him to “meet people in Kiev and Yalta of different political parties”, including the opposition leader Vitali Klitschko.

“They have never given me a line or influenced me. They pay travel costs and accommodation for me to attend the Yalta summit but on each occasion I have met people from every party,” he said.

The BUS, which has received secretarial support from Group DF, is chaired by Lord Risby.

The peer said: “I have never ever had any instruction from Firtash or had anyone ask me to take any political viewpoint. I made it clear that we would make a judgement about who we would see and that we would not be subject to any pressure.”

Mr Firtash – who owns a house near Harrods complete with an underground swimming pool – emerged in 2006 as one of the figures behind RosUkrEnergo, which controls the Russian company Gazprom’s gas supplies through Ukraine to Europe.

He is owner of Inter TV, Ukraine’s most popular television outlet, where journalists signed a petition complaining about alleged censorship and pro-Yanukovych propaganda in the run-up to the recent disturbances in Kiev.

However, Mr Firtash, who has in recent days also been linked to Mr Klitschko, states in his biography on the DF Group website that he “is not a member of any political party or movement”.

The Firtash Foundation denies it funded the BUS and said it has no relationship with it “beyond occasional discussions relating to culture projects in London”.