"We understand that a foot of concrete burst into the control room having been poured into an escalator void.
We await further information but what we do know is that LU technicians are on site now working flat out to clear up the mess and get services back on line, proving once again that its directly employed public sector staff who are needed to deal with this kind of emergency, making a nonsense of Boris Johnson's tube staff cuts plans."
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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