Royal Baby Watch: Due Date Arrives, No Baby

William, Duke of Cambridge and Catherine, the Duchess of Cambridge attend the trooping color parade in London on June 15, 2013 -- the annual trooping the color is to honor the Queens official birthday.

The world's media waited in the summer heat outside the private London hospital on Saturday where Prince William's wife Catherine will give birth, as the expected due date arrived with no sign of the royal heir.

A rumor that the Duchess of Cambridge had gone into labor on Thursday spread like wildfire on Twitter and reportedly caused Prime Minister David Cameron's office to call Buckingham Palace to check on it.

It was another false alarm, but the dozens of international journalists camped outside St Mary's Hospital are on tenterhooks, knowing that it could happen any day now.

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The palace has said the baby was due in "mid-July" and many editors have had this weekend in the diary for months -- even though any parent knows that babies rarely arrive on time.

William's father, Prince Charles, revealed his anticipation as he attended a festival celebrating Queen Elizabeth II's coronation on Friday.

The heir to the throne said "it won't be long now" until he becomes a grandfather as he surveyed a range of commemorative china to mark the new arrival -- one of countless ranges of memorabilia celebrating the birth.

His second wife Camilla added: "We are very excited. Immensely looking forward to it and waiting for the phone call."

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The popularity of William and Kate, who married in a glittering wedding at Westminster Abbey in 2011, has turned the birth of their first child into a global event.

Media organizations from around the world have been installed outside the hospital for almost two weeks now.

In the absence of news, time has been passing slowly. But at least the famous British rain has held off, with Saturday tipped to be the hottest day of the year so far.

For the television networks, the top priority is to hold their positions around the clock, working 12-hour shifts.

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That means fiercely defending their territory, never yielding an inch of space to a rival station, and woe betide anyone touching the gaffer tape marking out an organization's patch.

The main British news broadcasters -- BBC, ITN and Sky News -- have got the prime spots, lined up in front of the major US networks, which have maximized their space with some mammoth pieces of broadcasting hardware.

Behind them, it is a scramble to get a decent angle to shoot the doorway where William himself was first presented to the world in 1982, carried out of the Lindo Wing by his parents Prince Charles and Diana.

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