Two women are critically ill after a bus hit a group of pedestrians on Charing Cross Road late this afternoon.
An 18-year-old girl and a woman in her 40s are being treated in hospital.
A boy, aged 11, suffered minor injuries.
The road remains closed in both directions.
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The city is one of a small number which has seen an increase in traces of the Class A substance over recent years.
A goldfish from Buckinghamshire has survived an operation to remove a tumour. The surgery cost £200, the goldfish cost £3.
Most people woke up today to cold weather with heavy rain and cloudy skies.