The Green Party has issued an apology after its foreign affairs spokesperson, Tony Clarke, told national radio that a firm part-owned by Nathaniel Rothschild is bankrolling ISIS terror.

Tuesday morning Clarke told BBC Radio 5 : “There are British oil companies such as Genel Energy, run by Nathaniel Rothschild, one of George Osborne’s friends, who are making money, who are buying oil from ISIS, who are putting money into the pot, allowing ISIS therefore to fuel their evil across the world.”

The Green Party apologised on behalf of the former Labour MP for Northampton South on Tuesday night. In a statement, its press office said: “The Green Party and Tony Clarke apologise to Genel Energy for this false statement, which they have withdrawn and have undertaken not to repeat.”

“Genel Energy, in which Mr Rothschild is only a shareholder and non-executive director, is a producer of oil in the Kurdistan Region. It is not, and never has been, a purchaser of oil from anyone,” the statement continued.

Clarke later removed a link to the interview from his Twitter, where users accused him of peddling anti-Semitic conspiracy theories. He is an outspoken critic of Israel and in his blog last year wrote: “It is still very clear that the USA values the Jewish vote far higher than Palestinian life”.

The BBC said it had edited the comments from an online podcast of 5 Live‘s Breakfast programme after taking legal advice.

Clarke was expelled from Labour in 2005 after running against the party in the wake of an internal dispute.