Prince William and Kate Middleton (Pic:PA)
The world will watch in fascination today as Prince William marries Kate Middleton in a ceremony combining royal pomp and tender romance.
Months of meticulous preparations will come to fruition when the couple say their vows in Westminster Abbey in front of 1,900 guests and a global television audience of two billion.
Forecasters' warnings of rain showers over central London this morning failed to dampen the mounting excitement about the long-awaited royal wedding.
Heavy showers could fall on the royal couple's much-anticipated balcony kiss.
Although temperatures could reach 20C (68F) in the capital, there is a greater risk of rain as the early afternoon approaches.
William and his new bride are expected to appear on the balcony of Buckingham Palace at 1.25pm.
Billy Payne, a forecaster for MeteoGroup, the weather division of the Press Association, said: "There's a reasonable chance of a few heavy showers around at that time.
"We're expecting temperatures of up to 20 degrees, which is quite pleasant for this time of year. But fairly brisk north-easterly winds should take the edge off."
As wedding guests begin to arrive at Westminster Abbey from 8.15am it is likely to be cloudy, he said.
But this will probably give way to sunny spells from the late morning.
However, there is also a higher chance that rain could fall on Miss Middleton as she steps from the limousine at 11am on her father's arm to enter the abbey.
The forecaster added: "The later you go into the morning the higher the risk is of showers breaking out.
"Because the sun is quite strong, the showers will be heavy in nature with risk of thunder, particularly during the early afternoon."
Hundreds of thousands of well-wishers are expected in London to applaud the couple and enjoy the party atmosphere.
The weather looks set to be kinder to other parts of the UK that have featured in the royal love story.
At St Andrews in Fife, where the couple met as undergraduates, a wedding breakfast party with an expected 1,500 guests is forecast to be bathed in sunshine.
The wedding will also be shown on big screens outside the coffee shop at Balmoral Castle, near Ballater, Aberdeenshire.
One of the hottest UK spots promises to be in north-west Scotland where temperatures could hit 20C (68F).
Showers are predicted for Anglesey - where a series of celebratory events are scheduled. William works there as a search and rescue helicopter pilot and that is where the couple will have their first marital home.
Parties in Miss Middleton's home village of Bucklebury, Berkshire could also be hit by the same rain clouds threatening London.
But Helen Chivers of the Met Office said yesterday there was only a small chance of rain in London today.
She forecast sunny spells and predicted it should be dry when Miss Middleton arrives at the abbey.
Terry Hutt, 77, waits outside Westminster Abbey
A carnival atmosphere has spread across the capital
Well-wishers line the Royal Wedding procession route
Scores of well-wishers have been camped outside Westminster Abbey for days to get the best spot for the first full view of the bride's dress when she steps out of the Rolls-Royce carrying her to the service.
Miss Middleton, 29, will walk up the aisle on her father's arm as a commoner.
Just over an hour later she will leave, with her new husband by her side, as an HRH, a Princess and a future Queen.
Invited guests include David and Victoria Beckham, Sir Elton John and Guy Ritchie and Prime Minister David Cameron.
A host of politicians, clergy, military chiefs, ambassadors and more than 45 foreign royals will begin filling the abbey from 8.15am.
There too will be William's proud grandparents the Queen and Duke of Edinburgh, his father the Prince of Wales and stepmother the Duchess of Cornwall, joined by some 40 members of the British royal family, as well as close friends and confidantes of the couple.
William, 28, and his brother Prince Harry, 26, who is his best man, will arrive at the historic 1,000-year-old church at 10.15am.
By then the second-in-line to the throne may have been given a new title by the Queen, in a traditional gesture, to mark his wedding.
The groom, an RAF search and rescue helicopter pilot, will be dressed in red, wearing the famous scarlet tunic of an Irish Guards officer, rather than an Air Force uniform.
William faces a nailbiting 45-minute wait until his bride's arrival, part of which he will spend in private with Harry in the tiny side Chapel of St Edmund.
Kate spent her last night as a single woman with her parents, Michael and Carole, sister Pippa and brother James at the exclusive Goring hotel in Belgravia, a short distance from Buckingham Palace.
Kate arrived at the Goring Hotel last night in a black Jaguar car
She beamed with joy as she waved to crowds and spoke to hotel manager Jeremy Goring
William spent the evening at Clarence House with his family and gave royal enthusiasts on The Mall a treat as he went on an unplanned walkabout, admitting his "nerves" to the crowds.
As he spent several minutes shaking hands and thanking people for their support, he even joked: "All I've got to do is get my lines right."
Best man Prince Harry followed William and admitted to fans he had left his speech to the last minute.
He confessed: "I finished it yesterday. I thought it was a bit late."
Wills grinned from ear to ear as he went on his walkabout last night
He spoke to campers and asked whether they had the right overnight gear
Watch Wills go on his walkabout
Friends Sue Heppell, 59, Susie Record, 67, and Ann Burch, 65, travelled from Newcastle to find a good spot outside Clarence House at midday yesterday.
Mrs Record said she had met William last night and he had seemed very relaxed about his impending nuptials.
"He asked us whether we were sleeping out," she said. "He didn't seem surprised."
At exactly 10.51 today, the world will hope to get the first glimpse of Kate's dress, which has been kept a closely-guarded secret, when she leaves for the abbey.
However, they may have to wait, as the hotel has erected screens to ensure no-one catches a glimpse before she arrives at the abbey.
Hundreds of thousands of people are expected to line the mile-and-a-half route to Westminster Abbey, which takes in some of London's most famous landmarks as it passes through The Mall, Whitehall and Parliament Square.
Some 5,000 police officers are on duty as part of Britain's biggest security operation this century, amid continuing fears about the threat of terrorism and disruptive demonstrations.
The wedding service is a traditional religious affair with a strong flavour of "Britishness", and includes music by three of the nation's favourite composers, Elgar, Britten and Vaughan Williams.
The abbey has been decorated with an "avenue of trees" along the nave made up of eight English field maples and two hornbeams.
William and Kate's nuptials are the 15th to be celebrated at the holy site, which has witnessed 37 coronations over the centuries, beginning with William the Conqueror in 1066.
The wedding of this William comes more than a millennium after the first King William was crowned.
Kate is following in the footsteps of Diana, Princess of Wales, and will not promise to "obey" her new husband in her vows but instead to "love, comfort, honour and keep" him.
With William choosing not to wear a wedding ring, only he will say "With this ring I thee wed", as he places the simple, slim band fashioned from a nugget of Welsh gold on his bride's finger.
The Archbishop of Canterbury, Dr Rowan Williams, is marrying the couple, the Bishop of London, the Rt Rev Richard Chartres, will give the address, and the Dean of Westminster, the Very Rev Dr John Hall, is conducting the service.
The witnesses who sign the historic marriage registers during the ceremony will be the Prince of Wales, the Duchess of Cornwall, Harry, Kate's parents, her sister Pippa and her brother James.
The Archbishop of Canterbury, Dr Rowan Williams, will marry Wills and Kate
The guest list has provoked controversy, with the Foreign Office announcing the last-minute withdrawal of the Syrian ambassador's invitation yesterday in the wake of a bloody crackdown on protesters against president Bashar Assad.
Further questions have been raised about why former Labour prime ministers Tony Blair and Gordon Brown were not invited while Tory counterparts Sir John Major and Baroness Thatcher were.
After the ceremony, William and Kate will ride back to Buckingham Palace in the open-top 1902 State Landau, the same fairytale horse-drawn carriage used by Charles and Diana on their wedding day 30 years earlier - although if it rains, the newly-weds will use the Glass Coach.
The 1902 State Landau is Wills and Kate's choice of transport back to Buckingham Palace after the ceremony
At 1.25pm, the bride and groom will step out onto the Palace's famous balcony, joined by the Queen and their families to watch the thundering flypast of a Lancaster, a Spitfire and a Hurricane from the Battle of Britain Memorial Flight and Two Tornado and Two Typhoon jets.
Then, the moment the world will be waiting for - the long-awaited kiss, the first time William and Kate have ever done so in public.
There will be two receptions at the palace, one with canapes hosted by the Queen in the afternoon for 650 guests, followed by the Prince of Wales's more intimate black-tie gathering of 300 close family and friends in the evening.
The 85-year-old monarch will skip the evening party, missing Harry's best man speech, by heading out of the capital with the Duke of Edinburgh for a private weekend, allowing guests to party the night away in her official London home.
The Queen held a pre-wedding dinner last night for foreign dignitaries
Prince Albert II of Monaco and fiancee Charlene Wittstock
Sophie, Countess of Wessex and Prince Edward, Earl of Wessex
Princess Beatrice of York and Princess Eugenie attended the dinner at the Mandarin Oriental
The royal wedding is the culmination of a romance that began more than eight years ago when William and Kate met as students at St Andrews University in Fife, Scotland.
Their story has captured the hearts of people across the planet and thousands of foreign journalists, photographers and TV crews have descended on London to cover the event.
Millions of British workers are enjoying an extra public holiday to celebrate and many will attend one of the 5,500 street parties being organised across the country, including one in Downing Street.
Nowhere is more excited about the wedding than Kate's home village of Bucklebury, Berkshire, which is organising an extravaganza of parties to mark the local girl's big day.
Download the Daily Mirror's 'Wills & Kate A Royal Love Story' souvenir mobile app for iPhone, iTouch, iPad or Nokia smartphone hereView the original article here
Prince Charles and Camilla arrive for the wedding
Prince Harry and Pippa Middleton
Prince William and Kate Middleton
Princess Diana by Mario Testino
Kate Middleton and Prince William (Pic:Getty Images)
Princess Diana
Prince Charles
Today's Google Doodle celebrates the Royal wedding