Queen heads off on Hebridean adventure
It used to be one of the favourite episodes of the Queen's year.
She would always begin her annual Scottish holiday with a cruise around the Western Isles aboard the royal yacht Britannia.
The journey would culminate with a voyage along the northern coast of Scotland, past her mother's holiday home at the Castle of Mey just west of John O'Groats, before finally landing at Aberdeen, from where the Queen would travel inland to her estate at Balmoral.
But Britannia was decommissioned in 1997.
Proposals for a new royal yacht foundered on the rocks of political sensitivity over costs.
The Queen's annual Scottish cruise, with its impromptu landings on remote beaches where the royal family would picnic out of sight of prying eyes, seemed destined to be nothing more than a memory.
However in 2006, the Queen surprised everyone.
It was the year of her 80th birthday and she awarded herself a summer vacation afloat.
She chartered a former Caledonian MacBrayne car ferry which had been refitted and transformed into a small cruise liner called the Hebridean Princess" and sailed off for a nine-day "family holiday" around the Scottish islands.
By all accounts the family, which has not always been noted for its warmth and conviviality, had a very jolly time.
Perhaps it was the calming influence of the ocean, or simply the realisation that they were all trapped aboard the boat, so they had better make the best of it.
Whatever were the family dynamics of the royals afloat, it was clearly an experience which the Queen was keen to repeat.
So the MV Hebridean Princess has been summoned into royal service again, privately chartered by the Queen at a reputed cost this time of around £200,000.
According to Holyroodhouse, the vessel is to be the venue for a family celebration of the 60th birthday (in August) of the Princess Royal, and the 50th birthday earlier this year of the Duke of York.
So, somewhere in the seas off the Western Isles over the coming days, there will be a birthday party, or perhaps several birthday parties.
It will be a chance for a family which does not normally spend too much time together under the same roof, to relax in each other's company.
For the Queen herself it will be an opportunity to take a break from what has been a demanding year.
Quite apart from the routine engagements and duties which fill her schedule, there was an inconclusive general election which had to be navigated by the Palace.
Most recently, a nine-day tour of Canada was followed by a flying visit to New York, where she addressed the General Assembly of the United Nations and visited Ground Zero for the first time.
So while the cruise will be a chance for the royal family to mark the 50th and 60th birthdays of two of the Queen's children (and to anticipate the 90th birthday next year of her husband), it is the age of the Queen herself that, I suspect, most people will feel is the justification for this short maritime adventure.
She was 84 last April. She knows that there can never be any escape from her role.
But for a few days this summer, the seas and bracing winds off the Western Isles will give the Queen the closest thing to an away-from-it-all experience to which this notably frugal monarch will feel she is entitled.
It will re-kindle memories of happy times earlier in her reign when a much younger family sailed out aboard Britannia.
And it will end with another moment of family nostalgia because the cruise will conclude at her late mother's home at the Castle of Mey on the northern coast of Caithness at around the time of the 110th anniversary of the late Queen Mother's birth.
There the Queen and the other royal holidaymakers will come ashore to be entertained to lunch at the Castle of Mey by the Prince of Wales and his wife, before heading on to Balmoral for the remainder of her summer break.