AN elaborate plywood map, used by the military masterminds of the D-Day invasion, will be a permanent reminder of how the operation was planned.

Hundreds of visitors are expected to view the massive map, which is still on display at Southwick House at the former HMS Dryad base at Southwick, near Fareham.

Visits, which have to be organised in advance, were fully booked for this week of the 60th anniversary.

Southwick House was requisitioned by the navy in 1941 and became the forward planning and operational headquarters of the Supreme Commander of the Allied Expeditionary Forces, General Dwight D Eisenhower and the Naval Commander for Operation Overlord, Admiral Sir Bertram Ramsay, in early 1944.

The wall map in the drawing room, which became the wardroom, was used by the commanders to watch the progress of events on D-Day, June 6, 1944.

The massive plywood scale map, which was commissioned from toy firm Chad Valley based in Birmingham, covered the area from northern Norway to Spain.

When it was completed, a naval lieutenant and two carpenters transported it to Southwick by lorry amid high secrecy.

On arrival, the map was erected on the east wall of the drawing room by the two carpenters, who were kept at Southwick for several weeks to maintain the secrecy surrounding the invasion.

By June 1, 1944, Admiral Ramsay was joined at Southwick by General Eisenhower and General Montgomery. Many hundreds of people involved in D-Day were briefed at Southwick House, with the Allied Naval Command writing more than 3,000 orders for Operation Neptune, the naval aspect of D-Day.

The visitors' book also shows that more than 3,000 senior naval and Royal Marine officers from several nations were briefed there in the week before the invasion. HMS Dryad, the base on which Southwick House stands, was decommissioned in March.