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.
More top news
Premier League clubs could face heavy fines and even the prospect of points deductions if they fail to meet an August deadline.
Police have released CCTV of a man they wish to identify after an assault in Newham.
Piccadilly lights were switched off for modernisation work to take place. It's the longest time the lights will be off since the Blitz.