In the judgement this afternoon, Sir Robert Owen also agreed not to include any evidence questioning whether the UK authorities could have prevented Litvinenko's death.
The coroner admitted the exclusion of this evidence could result in the inquest becoming "incomplete, misleading and unfair" and took the unusual step of inviting the government to hear the secret evidence in a separate secret inquiry behind closed doors.
The inquest is scheduled to begin on 2nd October.
More top news
The high of 35C was recorded on a Bakerloo line train between Piccadilly Circus and Oxford Circus at 2pm.
Weather forecasters say temperatures could reach 35C, beating the previous record of 34.6C in the scorching summer of 1976.
After years of political manoeuvring over the future expansion of Heathrow Airport, there has been an important development this lunchtime.