1. When was the suggestion of support from Oleg Deripaska for the Conservatives first raised, and by whom?

Friends of financier Nat Rothschild have suggested that he and Mr Osborne first discussed a possible visit to Mr Deripaska before Andrew Feldman, the Tory chief executive, arrived at Mr Rothschild's Corfu villa on August 24.

Mr Osborne’s account, by contrast, says that it was Mr Rothschild who raised the possibility of a donation with Mr Feldman when he arrived, and that it was only then that a visit to the oligarch’s yacht was discussed. “At no point previously had Mr Osborne and Mr Rothschild discussed the possibility of a donation to the Conservative Party from Mr Deripaska,” according to the Tory account.

2. Who raised the possibility of channelling a donation through LDV, a British firm owned by Mr Derispaska, and why?

The Conservatives insist that Mr Feldman gave a routine explanation of electoral law, which bars overseas donations, and it was Mr Rothschild who first suggested using LDV as a way of getting funds to the party.

Mr Rothschild’s letter to The Times, however, says Mr Feldman “suggested...that the donation was 'channelled' through one of Mr Derispaska’s British companies”.

3. Was the question of a donation raised on the yacht in front of the Russian oligarch on August 24?

Mr Osborne’s denial is explicit. “There was no conversation or mention of party funding or the possibility of Mr Deripaska making a donation to the Conservative Party,” claims the account in the name of the Shadow Chancellor and Mr Feldman.

Mr Rothschild is equally confident. His statement last night insisted: “The subject of a donation by Mr Deripaska’s UK company also arose briefly while we were on the boat, but the conversation gained no traction.”

4. Was the subject of a donation then discussed over dinner between Mr Rothschild and Mr Osborne?

“At dinner at my house later that evening, the subject again came up in conversation, and Mr Osborne was interested in whether and how such a donation could be secured,” recalls the financier.

The Osborne and Feldman account does not address this claim.

5. Who decided that a donation would not be appropriate?

Mr Feldman says that, having taken advice, he decided not to pursue the option of a cash gift from LDV following a phone conversation with the financier.

Mr Rothschild contends that the Tory chief executive “again raised the issue of the donation with me. Mr Deripaska decided that he did not wish to make any donation.”

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