CCTV released by Westminster Council shows the moment an innocent shopper is targeted by a fraudster on Oxford Street.
A gang member can be seen bending down to pick up a ring - but in this case the target gets away without falling for it, after a warning from a council binman.
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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.