A £480m hospital rebuild in Brighton has been given final approval by the Treasury nearly a year and a half after it received the go-ahead from George Osborne.

Brighton and Sussex University Hospitals Trust will refurbish and rebuild its hospital buildings, which are some of the oldest in the NHS, using £484.7m from the Treasury.

Approval for the full business case was given shortly after the trust estimated delays would start to ramp up the cost of the “3Ts” redevelopment project.

In the trust’s board papers for September, chief executive Matthew Kershaw said if final approval was not given by “mid October” the capital costs would increase.

The trust was asked to provide “further assurance” because of its in-year financial position. It had a £17.6m year to date deficit at the end of August, which was £6m worse than its planned position. The trust forecasts to deliver a £16.7m deficit by the end of the year.

The trust was originally hoping for final approval for the building work in March.

Matthew Kershaw

The redevelopment is a ‘once in a generation opportunity’, Matthew Kershaw said

Building work will begin in January for the first of the two new buildings. Just under a quarter of the hospital site will be taken over by construction. All clinical services will be on site throughout the redevelopment and some will be moved to temporary accommodation.

All emergency and cranial neurosurgery work was moved from the Princess Royal Hospital to Royal Sussex County Hospital in June in preparation for the building work. A dedicated fractured neck of femur service has been created and inpatient urology services have been centralised at the Princess Royal.

The hospital rebuild is due to be completed in 2024.

Mr Kershaw said: “This redevelopment is a once in a generation opportunity to build on the excellent care we currently provide to our patients and truly improve acute healthcare for patients in Brighton and Hove and across the region. Today’s announcement marks a genuine turning point; the 3Ts redevelopment is no longer an ambitious plan, it is the future of this hospital.

“I would like to thank everyone who has contributed to the success of the project so far. A great deal of work has gone into bringing us to this point and there is still much more to be done. The result though, having a better hospital for all our patients and staff in the years to come, is worth all this effort and more.”