Rail passengers are being urged to avoid London Bridge station tomorrow if at all possible - because of fears of overcrowding.
With an onslaught of commuters as well as sports fans, station bosses are preparing for more people passing through than ever before.
Nick Thatcher reports.
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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.