Negotiations with the rival consortia will now go ahead to decide which offers the best prospects for preserving the vessel. They will focus in particular on arrangements to ensure that Britannia's use and appearance are properly safeguarded.
"After 44 years of distinguished service to queen and country, Britannia has a special place in the people's affections," said Mr Robertson.
"This was confirmed by the many thousands who turned out to see her around the country on her final tour and by the interest shown in her preservation."
It would be wrong to scrap the Royal Yacht if there were acceptable ways to preserve her "for the wider benefit of the public", he added, and described the seven preservation proposals as "high quality" and very imaginative.
He said the proposals from Forth Ports for Edinburgh and Peel Holdings for Manchester stood out from all the rest with funding in place and firm costed plans for the appropriate preservation and care of the ship.
"We will therefore disappoint some organisations who have worked very hard on their proposals," he said.
If the proposal by Forth Ports were successful, Britannia would be berthed on Edinburgh's waterfront at Leith alongside a planned multi-million pound ocean liner terminal designed by Sir Terence Conran.
It would be used for corporate hospitality and state functions with public access at other times. The consortium claims no public money or funds from the National Lottery would be required.
If the Peel Holdings proposal should win, Britannia would be berthed in a 16 acre Heritage site at Trafford Park. It would be moored adjacent to the historic Barton swingbridge, close to a new shopping and entertainment complex.
Britannia will be decommissioned at an emotional ceremony in Portsmouth naval base tomorrow attended by the Queen, the Duke of Edinburgh and other members of the Royal Family.Reuse content