Update: It has been confirmed that a mixture of concrete and water has flooded a Victoria Line control room. The line is closed between Warren Street and Brixton, with severe delays on all other sections. A limited replacement bus service is in operation.
The story was scooped by Us Vs Th3m, and has since been confirmed by a Transport for London spokesperson.
If you're planning on heading home any time soon, avoid the Victoria Line.
So, quite a serious flood, then. The plot thickens (literally) when you see this report over on Us Vs Th3m. The site's as-yet unsubstantiated explanation is that a control room has been accidentally flooded by quick-setting concrete. We repeat that this hasn't been officially verified.
In response to enquiries about the rumour, @VictoriaLine replied 'No, I can't confirm that', but wasn't able to deny it either. The mishap is utterly bizarre if true, or an utterly brilliant wind-up if false.
We'll update this story with any developments, or if the rumour of concrete is...reinforced.
Update 5.15pm: Us Vs Th3m stands by its story, but won't say how it got the concrete photos.
Update 5.30pm: The rumours of a concrete spill appear to have been confirmed by Transport for London.