Prince Harry will tonight fly out of the UK to Australia without seeing his new niece or nephew . A disappointed Prince Harry will tonight fly out of the UK to Australia without seeing his new niece or nephew. With the Duchess of Cambridge now overdue for the birth of her second child, the prince will not be able to meet the new royal baby until he returns to this country in mid May. Harry, who will be bumped down to fifth in the line of succession by the new arrival, had returned briefly at the weekend to hand out prizes at the London Marathon after undertaking several engagements in Turkey to mark the centenary of the Gallipoli campaign. He was dragging out his return until tonight in the hope of getting to meet the new little prince or princess. But with Duchess now several days overdue, Harry is being forced to return to Australia where he is on a month-long placement with the army, followed by a week long official tour of New Zealand. Instead he spent time playing doting uncle to his nephew, Prince George, who turns two in July, at the Cambridge's apartment at Kensington Palace. Kate and her husband, Prince William, had been told to expect their new son or daughter – who will be fourth in line to the throne – by Saturday, according to sources. The Duchess – whose son, Prince George, was also around a week late - herself told well-wishers earlier this year that the new little prince or princess was due 'mid to late April'. When Prince George's little brother or sister is born the news will be revealed to royal correspondents in a press release followed by an announcement two minutes on the Kensington and Buckingham Palace social media accounts on Twitter and Instagram. Details of their arrival – including their six, birth weight and details of the attending medical staff - will then be posted in the traditional way on an easel outside Buckingham Palace. Scroll down for video . Although palace officials have barred media from camping outside the private Lindo Wing at St Mary's Hospital in Paddington, where Kate is due to give birth, in order to prevent what they describe as a 'media circus', excitement was mounting yesterday with royal 'superfans' continuing their own round-the-clock vigil. The Duchess – whose son, Prince George, was also around a week late - herself told well-wishers earlier this year that the new little prince or princess was due 'mid to late April' Harry had returned briefly at the weekend to hand out prizes at the London Marathon after undertaking several engagements in Turkey (pictured) to mark the centenary of the Gallipoli campaign . The mounting tension saw bookmakers' cash in with a flurry of bets on everything from the time of birth to the new baby's name – and even their hair and eye colour. Prince Harry will no doubt be encouraged to see that 4/1 odds are being offered for the baby to be a fellow red head. Ladbrokes customers appeared to favour Arthur for a boy, with odds collapsing to 8/1, and Alice remaining the hot favourite for a girl with odds of just 5/4. Some were still hankering after Diana (14/1), in memory of William's late mother, or even Elizabeth in honour of the Queen (6/1). The firm said one male customer in the Manchester area had bet £10,000 on the new baby being a girl, the largest single wager so far received. Spokesman, Jessica Bridge, said: 'As far as the money is concerned they will soon welcome Princess Alice into the family.' Coral said yesterday that it had seen a slew of bets come in that the baby will arrive today (Monday) – now 6/1 joint favourite – with odds of 10-1 that the nation is still waiting at the end of the week. Many bookmakers are also offering 4/1 odds of the couple welcoming their new child into the world on Wednesday – their fourth wedding anniversary. Prince William and Kate pose with their son Prince George at the National History Museum in London . Preparations have been made outside the Lindo Wing of the hospital for the huge crowds expected to welcome the royal birth - with the Duchess said to be up to four days overdue . As the 'spare to the heir', it is unlikely that the duke and duchess's new baby will accede to the throne – although it is not unheard of. Most recently the Queen's own father became King George VI when his elder brother, King Edward VIII, unexpectedly abdicated over his love for 'unsuitable' American divorcee Wallis Simpson. Thanks to recent changes in the law of succession, if the new baby is girl then their claim to the throne cannot be superseded by a younger brother, should William and Kate go on to have a third child. She will also be known as HRH Princess (forename) of Cambridge after the Queen altered a century-old ruling in the run up to Prince George's birth which had meant that only the eldest son of a Prince of Wales (as well as the children of a monarch and the sons of those children) was entitled to the honour. The new arrival will also bump Prince Andrew out of the 'top five' for the first time. He will drop to sixth in line to the throne. His eldest daughter, Princess Beatrice, will find herself relegated to seventh – the advantage being that she will no longer require the Queen's approval for her marriage. Her younger sister, Princess Eugenie, will become eighth. If the baby is a girl it will be the first Princess of Cambridge to be born for 182 years. Kate has said in the past that she favours a boy but that her husband rather likes the idea of a girl. Grandfather Prince Charles has said he would like a girl – while his late wife, Diana, Princess of Wales, always longed for a daughter.
Prince Harry will  fly out of UK tonight to continue placement in Australia . This means he will not be able to meet royal baby until return in mid-May . He will be bumped down to fifth in the line of succession by the new arrival . Duchess of Cambridge is several days overdue for birth of second baby .