Building a new breast care unit in Haywards Heath could cost more than a unit in Brighton, health chiefs have been warned.

Campaigners fighting to keep the Nigel Porter Unit for Breast Care in Brighton feared a new unit in Haywards Heath could succeed because it was estimated to be a cheaper option.

However, health bosses have now admitted the figures are out of date.

The original proposal was to close the unit and move it to a building on the Princess Royal Hospital site in Haywards Heath, at a cost of about £3 million.

However, architects told health officials the building was not suitable and plans for a new building were drawn up.

It was estimated a new unit at Haywards Heath would cost about £7 million, compared with £10 million to demolish and rebuild a unit on the Rosaz House site in Bristol Gate, Brighton.

However, a report from Mid Sussex District Council planning officers revealed the Haywards Heath option was far more complex than originally thought.

A spokesman for the Brighton and Sussex University Hospitals Trust, said: "The prices we issued last year are well out of date.

"New costs are being looked at but the decision on September 27 will not just be about cost."

Campaigners demanding the unit remains in Brighton said they were confident the Haywards Heath option would prove more expensive.

Brighton and Hove City Councillor Jayne Bennett, who wants the unit to stay in Brighton, said: "We knew it wouldn't be easy to build a unit in Haywards Heath but the Brighton application was straight forward."

Outline planning permission for the Brighton site was granted when plans were presented to the city council on July 3.

The trust was forced to submit two applications for outline permission for the Princess Royal site, for buildings of different shapes.

The options received planning permission but with a large number of conditions, which could prove costly.

One of the designs would lead to the loss of 85 car parking spaces, which the trust would be forced to reallocate around the hospital site.

Conditions also stated landscaping must take into account existing trees and hedges and the external appearance of the building.

The final costings for both sites will be made public before the final decision in September.