West Oxfordshire and Witney Liberal Democrats say the Pandora Papers "raise serious questions" about donations to the MP for Witney and West Oxfordshire Conservatives from the wife of a former Russian oligarch.

The Pandora Papers is a leak of almost 12 million documents and files exposing the secret wealth and dealings of world leaders, politicians and billionaires.

The data was obtained by the International Consortium of Investigative Journalists in Washington DC and more than than 600 journalists from 117 countries have worked on the story.

Witney MP Robert Courts and West Oxfordshire Conservatives have received just under £18,000 from Lubov Chernukhin, wife of the former Russian minister Vladimir Chernukhin.

Mrs Chernukhin has given more than £1.8million to the Conservative Party since 2012.

According to The Guardian and BBC Panorama, which have led the investigation in the UK, leaked documents reveal her personal wealth comes from her husband, a former Putin ally.

The documents in the Pandora Papers leak of internal files and correspondence from offshore financial firms show the couple are linked to a network of 32 companies, three trusts and more than £100million in assets.

One email describes her as being "financially supported by her husband", and another as "a housewife", said BBC Panorama.

One document shows Mr Chernukhin's offshore company loaned £4million to his wife's UK company.

Pandora Papers documents reveal how they secretly acquired properties in the UK through offshore companies, BBC Panorama reported.

They purchased a house overlooking Regents Park in London now worth £38million, as well as a mansion in Oxfordshire bought for £10million.

Mrs Chernukhin's lawyers say she is a British citizen and is entitled to do as she wishes with her money.

Her donations to the Conservative Party have seen the 48-year-old win auction bids to play tennis with Boris Johnson and she has had dinner with Theresa May, when she was prime minister.

The Lib Dems said revelations in the Pandora Papers of "a web of shell companies that support the activities of the Tory donor and her husband demand further investigation".

They called on Mr Courts to return the £17,975 pending a review of the sources of the couple’s wealth.

Chair Carl Rylett said: “At the local level, the £14,975 that the Tory party received in February from Mrs Chernukhin could pay for thousands of Facebook ads or leaflets and have a big impact on the outcome of next year's local elections.

“We need to know where that money has come from. In the short term, we ask Robert Courts to show leadership by returning the money until we have clarity.”

Mr Courts said: "All donations made to the local Conservative Party are received in accordance with UK law and registered with the Electoral Commission.

"The individual in question is a British citizen and is therefore entitled to make political donations."