Contractors have started work to dismantle the Olympic Equestrian arena at Greenwich Park.
But local people have questioned why the work to restore the park has taken so long.
But the London Olympic Committee says it is on track to hand back control of the area to The Royal Parks next month.
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The 20-year-old was found fatally wounded on Roth Walk, near Finsbury Park, north London at around 3am on Saturday, Scotland Yard said.
Police have arrested a man wanted in connection with a burglary at the home of pensioner Richard Osborn-Brooks.
The rally comes after it emerged that the Home Office destroyed thousands of landing cards documenting the arrival of windrush-era migrants