Prolonged wintry conditions or another outbreak of norovirus will see A&E departments across the country reach "breaking point", NHS leaders have warned.
The emergency care system has come under intense and increasing pressure in recent years, with over a million more people attending emergency departments compared to 2010.
Labour has accused the Government of leaving A&E departments "on the brink of a serious crisis", a claim apparently supported by a series of separate surveys of leading medics, nurses and voters that suggested patients are at an increasing risk.
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A small number of people were treated at Southgate Tube station, British Transport Police said.