Final negotiations are taking place between Gosport Borough Council (GBC) and Portsmouth Naval Base Property Trust in a bid to secure the future of a naval museum at Priddy's Hard, Hampshire.

The Property Trust, which already holds a 99-year lease to Portsmouth Historic Dockyard from the Ministry of Defence (MoD), is seeking to acquire the Explosion! Museum of Naval Firepower in a bid to unite historic sites on both sides of Portsmouth Harbour. Explosion! first opened in 2001 at the heart of a 22-acre (8.9-hectare) former ordnance depot at Priddy's Hard, which was acquired by the council from the MoD in 1994. However, GBC is now seeking to dispose of the museum as it says it is unable to invest in developing the site further.

The Property Trust now plans to introduce a summer waterbus service linking Portsmouth Historic Dockyard to Priddy's Hard, the Royal Navy Submarine Museum and Gunwharf Quays as part of a bid to promote the harbour as one of the world's leading heritage sites. Peter Goodship, Property Trust chief executive, said: "We hope that by saving Explosion! from closure, we can realise our ambition of uniting the two sides of the harbour as originally intended by the Renaissance of Portsmouth Harbour scheme.

"Portsmouth Harbour is one of the finest historic sites in the world and deserves to benefit Portsmouth, Gosport and Fareham in the same way as Cardiff Bay benefits the Cardiff community and Sydney Harbour benefits Sydney."