Extraordinary blunder of signalling swamped by concrete

. Credit: Us Vs Them/@UsVsTh3m

Tens of thousands of tube commuters are paying the price tonight for an extraordinary blunder by workmen.

A key section of the Victoria Line is at a standstill after crucial signal equipment was swamped by liquid concrete.

. Credit: Us Vs Them/@UsVsTh3m

The accident involved contractors working on the £695m project to expand Victoria Underground station.

. Credit: Us Vs Them/@UsVsTh3m

Concrete being used to reinforce new excavations flooded a signal room. Underground bosses say human error was to blame.

. Credit: Us Vs Them/@UsVsTh3m

Engineers are now in a race against time to try to remove the concrete before it sets.

The Victoria Line - which carries 500,000 passengers a day, was suspended between Warren Street and Brixton shortly before this evening's rush hour.

The line is unlikely to re-open tonight and services may still be at a standstill tomorrow morning.

Read more: London Underground's response here