Sister Gladys Gonsalves, who has worked in the service for 27 years, cut the ribbon on the new facility in front of invited local MPs, city councillors, healthcare partners and other guests.

Dr Andy Heeps, chief executive of University Hospitals Sussex, said: ‘Opening our new acute medical unit is superb news for thousands of patients today, and even better for hundreds of thousands of future patients as it enables us to start renovating the main emergency department.

‘Over the next three years, we will be modernising the old and tired A&E – but as the region's major trauma centre, we cannot close the department. Instead, we must complete the building works in phases alongside our teams providing life-saving care. It's like conducting open-heart surgery on the hospital while caring for more than 300 A&E patients every day.

‘So, I do want to be candid: this is going to be a challenging time. Our staff will be working in difficult, temporary and cramped circumstances, and patients and families will also experience this. We ask for their patience and understanding, because this is the only way we can deliver the excellent urgent and emergency care facilities our patients and hard-working teams deserve.'

Dr Charlotte Canniff, ICS joint chief medical officer, said: ‘We're proud to be investing £50m in this new acute medical unit, which will help ensure patients across Sussex can be seen, diagnosed and treated more quickly when they need urgent care.

‘This modern facility will mean more people can start treatment sooner and, where appropriate, return home the same day, improving both patient experience and outcomes. It's a significant step forward in strengthening hospital care for our communities and making sure people across the region benefit from faster, more efficient services.'