Network Rail and TfL have dismissed reports of a gas leak and said that overground and underground train services are running as normal.
Although four people have been taken unwell at London Bridge Station this morning, the Metropolitan Police has said there was nothing to link the cases at this stage.
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The former London Mayor also claimed Tony Blair's decision to ignore security advice had "killed 52 Londoners".
The victim, a woman in her 40s from Hillingdon, west Londion, was conned into handing over the fortune to a man who faked his name.
Inspectors found a culture of bullying and major problems with poor ambulance response times at the trust, which is the biggest in the UK.