Patients have been urged not to attend A&E unless it is a lifesaving emergency after a critical incident was declared at two hospitals.

University Hospitals Sussex NHS Foundation Trust said both the Royal Sussex County Hospital in Brighton and Princess Royal Hospital in Haywards Heath were affected by problems with IT and phone systems last night.

Ambulances are being diverted and patients are being taken to different hospitals.

The trust said St Richard’s Hospital in Chichester and Worthing Hospital are also under “considerable pressure” while they help support the Royal Sussex and Princess Royal.

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A hospital spokesman said: “Please do not attend our emergency departments unless it is a lifesaving emergency. Patients are being strongly advised to consider alternatives to these services apart from lifesaving emergencies.

“For any urgent health support, please use NHS 111 online or by phone to receive advice and direction to the most appropriate service.

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“Declaring a critical incident allows staff to focus on the needs of their patients, and for the Trust to seek support from local partners. The disruption is widespread, and frontline teams are affected.

“Bringing IT systems back to normal is a priority, and teams are working to do that this evening. We will update everyone further in due course.”

An update from the trust at 11.30pm last night said “progress has been made in restoring IT systems”.

The critical incident was declared at 10pm.

However it added: “Please be aware that this is still an ongoing issue, despite the improved situation. Anyone who does not need an emergency department should visit or call 111 for help or advice.”