Quick thinking from engineers prevented cement from setting in the Victoria Line signal room which would have caused even further disruption to commuters.
Peter McNaught, operations director for the Bakerloo, Central and Victoria lines, said it was lucky workers knew sugar would stop the cement setting.
Normal service has resumed on the line after engineers worked throughout the night to repair the damage.
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Police are looking for a man who sexually assaulted a 12-year-old girl at a London train station yesterday while she was with her family.
A gang of robbers who dressed in burkas to stage raids on high-end stores in London have been convicted today.
The retrospective is so in-demand the museum will open its doors all through the night for the first time since it opened in 1857.