They're more than twice the height of Nelson's Column - they've come halfway round the world - and they signal the latest stage of work on a project which will create 12,000 jobs.
Three cranes, the biggest ever seen in Britain, arrived from China this morning at the London Gateway in Essex.Our Political Correspondent Simon Harris explains exactly why they are here.
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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.