A museum which tells the story of the D-Day landings is set to secure a £4.1 million Heritage Lottery Fund (HLF) grant to transform the centre to bring the exhibitions to life for visitors of the 21st century.
The funding announcement for the Portsmouth D-Day Museum comes as the city is at the centre of events, along with Normandy, to mark the 70th anniversary of the invasion which changed the course of the Second World War.
The HLF has given its "initial support" for the plans which will completely renew the museum and displays in time for the 75th anniversary in 2019.
It has already approved a development grant of £224,000 to enable the process of creating detailed proposals to begin.
Carole Souter, chief executive of HLF, said: "The D-Day landings were a monumental moment in European history, involving more than a 150 thousand men from the British and Allied forces.
"As we head towards the 75th anniversary, HLF's trustees felt the plans set out for a refreshed, revamped D-Day Museum would help bring this story alive for a new generation."
Dr Jane Mee, head of museums and visitor services for Portsmouth City Council, said: "2014 is also the 30th anniversary of the opening of the D-Day Museum and it is fitting that this project gets under way now while Normandy veterans are still with us and able to help us reshape the museum and its displays.
"Although focussed on the south coast, D-Day involved the whole country. Through this project, the museum will also create resources and partnerships to help individuals and communities nationally discover their wider D-Day heritage and subsequently share it through a major new website, conference programme, online resources and activities."
The plans include proposals to open up internal spaces and create dramatic new displays, extensively use the experiences and words of Normandy veterans to bring the story to life for visitors.
There will also be work done to create a new activity space and to continue work with young people and schools to ensure that the museum remains relevant to present and future generations.
Viscount Montgomery of Alamein - son of the Allied Ground Forces Commander on D-Day, General - later Field Marshal - Sir Bernard Montgomery - said: "The invasion of Normandy in June 1944 was the largest single military operation in the history of warfare. It represented a massive effort in planning, co-ordination, leadership, courage and dedication to duty. It is important that it should be remembered for many years to come."
George Batts, general secretary of the Normandy Veterans Association (NVA), said: "The Normandy landings were a turning point in the Second World War, and were only achieved through the service and sacrifices of hundreds of thousands of men and women from the Allied nations, whether in Normandy or in supporting roles in the UK and elsewhere.
"We Normandy veterans are very pleased to hear this news, particularly as it comes just before the 70th anniversary of D-Day.
"It is important that the contribution made by Normandy veterans and the story of D-Day are remembered for many years beyond the anniversary, and the D-Day museum's project will achieve this."
TV historian Dan Snow, who is an advocate of the museum, said: "The D-Day Museum in Portsmouth is the only museum in Britain that focuses solely on this vitally important chain of events.
"Its extraordinarily diverse collections bring together in one place the human stories behind D-Day and Operation Overlord.
"No other museum can provide such a uniquely dedicated insight into the roles of the millions of men and women that played a crucial part in the build-up to D-Day, as well the opportunity to be inspired by and reflect upon the sacrifice and heroism of those who took part."
The museum now needs to raise £160,000 towards the development costs which are being supported by Portsmouth City Council and the Dulverton Trust, the founder of which commissioned the Overlord embroidery, the UK's modern-day equivalent of the Bayeux Tapestry and a centrepiece of the museum.