* Four days of festivities begin with Epsom Derby
* Celebrations include Thames pageant and pop concert
* Tributes paid to queen's "incredible service"
By Michael Holden and Mike Collett-White
LONDON, June 2 Britain's Queen Elizabeth marks
60 years on the throne on Saturday with a visit to the races,
indulging a lifelong passion for horses and launching four days
of nationwide celebrations to honour a monarch riding high in
The 86-year-old will watch the Epsom Derby in southern
England, joining a crowd of up to 150,000 racegoers dressed in
their summer best for one of the racing season's highlights.
The focus then turns to London, where huge crowds are
expected to line the streets and the River Thames for a series
of spectacular events, although forecasts of rain and
unseasonably cold weather could dampen enthusiasm.
Millions more are expected to attend street parties across
the country as the nation marks the queen's personal milestone
under the banner of the "Diamond Jubilee".
"The queen has given incredible service," British Prime
Minister David Cameron said.
"She's never put a foot wrong, she's hugely popular and
respected here and around the world and it's an opportunity for
people to give thanks and to say thank you for the incredible
service that she's given."
Across Britain, red, white and blue "Union Jack" flags
billow from street lamps, outside buildings, shop fronts and
houses, and sales of patriotic souvenirs have rocketed ahead of
To royalists, the occasion is a chance to express their
appreciation of a woman who learned she was queen at the age of
25 while on holiday in Kenya with her husband Prince Philip.
For others, the chance of some extra days off work and to
enjoy the sort of extravaganza and public ceremony for which
Britain is renowned has made it a welcome break from austere
times, pay freezes and deep public spending cuts.
Republicans hope the occasion marks the last hurrah of a
dying anachronism, while some 2 million people are leaving
Britain altogether to go on holiday.
Having acceded to the throne in February 1952 on the death
of her father George VI when Winston Churchill was prime
minister, Elizabeth is now the longest-lived British monarch.
Only her great-great-grandmother Victoria spent longer on
the British throne and is the only other monarch to have
celebrated a Diamond Jubilee.
As well as being head of the Commonwealth of nations mainly
made up former British colonies, Elizabeth is also the Supreme
Governor of the Church of England.
"I think we've been enormously fortunate in this country to
have as our head of state a person who has a real personality -
a personality that comes through more and more, I think, in her
public utterances," said the Archbishop of Canterbury Rowan
Williams, the spiritual head of the Anglican Church.
On Sunday, a flotilla of 1,000 boats assembled from around
the globe will travel 25 miles along the River Thames to
accompany the queen and her 90-year-old husband on a royal
barge, in the largest such pageant for 350 years.
Thousands of street parties are also planned across Britain,
including one on Downing Street outside Cameron's office, as
part of a "Big Jubilee Lunch".
The queen's London residence Buckingham Palace will play
host to a pop concert on Monday featuring the likes of Paul
McCartney and Elton John, before a network of beacons will also
be lit across Britain and around the Commonwealth.
The celebrations culminate on Tuesday with a memorial
service at St Paul's Cathedral, a carriage procession through
central London and flypast by present and former royal air force
Large crowds are expected, with estimates that about a
million people will travel to London on Sunday alone. Not all
will be cheering for the queen, however, with banner-waving
republicans protesting at Tower Bridge during the flotilla.
Officials say there are some 9,500 street parties planned in
England Wales and ABTA, the British travel association, said
almost 2.5 million Britons were expected to take part.
London's Heathrow airport said some 780,000 people were due
to arrive in the next few days, although ABTA also said an
estimated 2 million Britons were planning to head overseas to
take advantage of the two extra public holidays.
Police said the weekend would include the largest royal
security operation ever conducted. Some 13,000 officials
including about 6,000 police officers will be on duty for the
Thames pageant, which poses challenges never before encountered.