Later today, the royal row barge 'Gloriana', will be placed in the water the first time.
It will lead the flotilla of boats during the Diamond Jubilee river pageant, ahead of the Queen's boat the 'Spirit of Chartwell'.
Specialist craftsmen have spent the last 18 weeks creating the vessel in a secret location.
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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.