The London Ambulance Service says it expects its 999-call computer system to be back up and running "in the next hour or two."
A spokesman said that the technical issue had been identified and that they were now bringing the system live again.
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If you're dreading going to work Monday morning, how about this for a career change.
Police have released more images of people wanted in connection with what they describe as 'disorder' at a McDonalds in central London.
Four teenage girls, one of them aged 15, have been arrested following what police are describing as "disorder" at a McDonalds branch.