THE occasion was all so terribly British.

The late summer afternoon sun glinted on the ripples of Southampton Water and the band of the Royal Marines caught the moment perfectly as they struck up Rule Britannia.

As the stirring music flowed out from the quayside, the most famous liner in the world, Southampton's icon of style and elegance, Queen Elizabeth 2 pulled herself away from her usual berth to begin a voyage that is to be far from usual.

Three deep, booming blasts, that could be heard ten miles away, shuddered through the air from QE2's powerful whistle, the water between dockside and ship boiled and churned with the movement of the great Cunarder and with another resonating blare she was off heading out to sea.

The Royal Marines, resplendent in traditional white pith helmets, marched along the dock, by now appropriately playing A Life on the Ocean Wave and that was exactly what this special, memorable event was celebrating.

QE2 was setting sail on her 1,400th voyage, a "lap of honour'' around Great Britain, to mark the 40th anniversary of her launch by the Queen back in 1967.

Over those decades QE2 has become a major part of Southampton's maritime heritage and has carried the city's name, emblazoned on her hull, across the great oceans to all corners of the globe.

So it was only right that the anniversary celebrations should begin in her home port of Southampton with a gala reception and lunch for more than 330 speciallyinvited guests on Saturday.

Heading the exclusive gathering was former Prime Minister, Baroness Thatcher, wearing a bright blue dress, who was escorted into the liner's Queen's Room, where she was met with a round of applause, by the liner's master, Captain Ian McNaught, and Cunard president, Carol Marlow.

Margaret Thatcher has a unique link with QE2 as it was while she was in Downing Street that the order went out to call-up the liner as part of the South Atlantic Task Force during the 1982 Falkland War.

The reception and lunch was quite a Thatcher family affair as her daughter, Carol, has her name on a new book tracing the history of QE2 from her inception right up to the present day.

Mingling with the guests was also the author, Dame Beryl Bainbridge, who once famously wrote: "To sail on QE2 is to know why Britain was once the envy of the world.

'' Former hostage Terry Waite, Jennie Bond, the BBC's one time royal correspondent and contestant in I'm a Celebrity Get Me Out of Here!, Coronation Street favourites Peter Baldwin, who played Derek Wilton in the long running soap opera, and Thelma Barlow, his long-suffering television wife, Mavis, and many retired captains of QE2 all raised a glass to toast the ship's anniversary.

Over the next week the voyage, which was sold out almost immediately it went on sale, will see QE2 visit Newcastle, South Queensferry for Edinburgh while tomorrow, the actual date of the anniversary, the liner will be making an emotional return to the River Clyde where she was built in the 1960s.

Friday will be another nostalgic day with QE2 alongside Liverpool, so long the base for Cunard, where, at the city's Anglican cathedral, a concert is to be held featuring the opera singer, Lesley Garrett, the Band of the Scots Guards and the Royal Liverpool Philharmonic Orchestra and Choir.