According to a report in the Sunday Telegraph, the letter from the Osborne indicates that the proposed deal would be would be eligible for £10 billion of financing guarantees.
EDF has previously said it is “in no hurry” to agree a strike price with the British government for the Hinkley Point C project.
Its chief executive Henri Proglio has said he is prepared to let negotiations “fail” if he doesn’t receive the required benchmark for a “strike price”, which would guarantee the scheme is profitable.
It is understood that EDF would like to achieve at least £100 per MWh, while the government is said to prefer a deal closer to £80.