South Central Ambulance Service has declared a critical incident tonight as it struggles to cope with the amount of 999 calls it is receiving this evening.
People in Bedfordshire, Buckinghamshire, Oxfordshire and Hampshire, are being urged to use the emergency number 'wisely'.
A spokeswoman said: "South Central Ambulance Service has declared a Critical Incident due to extreme pressures across our services.
"Our staff and volunteers are working extremely hard to respond to calls but the volume is overwhelming.
"Please, please, support us by using our services wisely, we’re here for life threatening illnesses and injuries.
"Thank you so much"
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Earlier this week Primer Minister Boris Johnson was warned to implement Covid "Plan B plus" for the winter or risk an NHS crisis.
NHS Confederation boss Matthew Taylor, which represents the healthcare systems in England, Wales and Northern Ireland, said the new curbs were needed or the UK would "risk stumbling into a winter crisis".
Mr Taylor said action needs to be brought in now or it will derail efforts to tackle the backlog of five million patients waiting for treatment.
He said: "We are right on the edge – and it is the middle of October. It would require an incredible amount of luck for us not to find ourselves in the midst of a profound crisis over the next three months.
"The government ought to not just announce that we’re moving to Plan B, but it should be Plan B plus.
"We should do what’s in Plan B in terms of masks… working from home, but also we should try to achieve the kind of national mobilisation that we achieved in the first and second waves, where the public went out of their way to support and help the health service."