He may be pushing 94, but Prince Philip’s not lost one iota of his sense of humour. Watching his wife sign an empty picture mount – in which a glossy portrait of the monarch was later placed - the on-form royal remarked waspishly: ‘It’s not a very good likeness, is it?’ Philip had accompanied the Queen to Southampton to officially name the new £473 million P&O cruise liner Britannia, in which the finished photograph will, eventually, hang. Scroll down for video . Cheeky: He may be pushing 94, but Prince Philip proved he hasn't lost one iota of his sense of humour today as The Queen launched the Britannia ocean liner in Southampton . And it wasn’t the only cracker uttered by Philip during the course of their visit. On being introduced to P&O’s Human Resource director, Paula Porter, yesterday, he remarked: ‘Humans are not resources!’ Fortunately the executive took the off-the-cuff comment in her stride, laughing afterwards: ‘I thought it was a very good line. I shall be using it again.’ The Queen, 88, also appeared to be thoroughly enjoying herself, even tapping her feet in time to the music of the Band of the Royal Marines as they played a merry jig before Britannia’s official naming ceremony. Wit: Watching his wife sign an empty picture mount – in which a glossy portrait of the monarch was later placed - the on-form royal remarked waspishly: ‘It’s not a very good likeness, is it?’ Tears of laughter: The Queen chuckled during the ceremony and wiped away a tear of laughter . Nowadays the monarch doesn’t actually have to swing the bottle of bubbly – in this case a Nebuchadnezzar (20 bottles) of English sparkling wine from the Wiston Estate Winery near Pulborough, Sussex – used to christen the boat herself. Instead she discreetly presses a button and the work is done for her. The new mechanised system isn’t entirely foolproof, however. When the bottle struck the side of the ship it exploded with an almighty bang, sending one hefty shard of glass speeding to within a few feet of where the Queen was sitting. Fortunately the forward-thinking people from P&O had erected a plastic screen to protect the elderly sovereign. All the same, it was quite a moment and clearly struck a chord with the guest of honour. When the Queen met a line-up of chefs later, including Marco Pierre White, she referred to the incident exclaiming: ‘It exploded!’ Olly Smith, Britannia’s wine expert, replied: ‘It did, didn’t it, Ma’am? Spectacularly' Round of applause: The Queen cheers during the naming ceremony for Britannia . Having a chat: The Queen enjoys a chat during the naming ceremony for Britannia . Round of applause: The Queen claps as the sixth cruise ship she has sponsored is officially named . Enjoying the sunshine: A dapper Duke of Edinburgh appeared to be enjoying his day in Southampton . Is that you dear? The Duke of Edinburgh flips through the programme and stops at a picture of the Queen . Thankfully, however, some traditions haven’t gone by the wayside. ‘God bless her and all who sail in her,’ the sovereign also said. Surprisingly, Buckingham Palace confirmed yesterday, the Queen has only named four civilian ships previously (the QE2 in 1967, Oriana in 1995, Queen Mary 2 in 2004 and Queen Elizabeth in 2010, with the Britannia as the fifth). But the monarch appeared to be thoroughly enjoying herself, chatting nineteen to the dozen with other VIP guests as she toured the vessel. She was heard telling TV chef James Martin, one of a number of celebrity chefs who will be offering classes for passengers: ‘The first time I ever saw white bread was on board the old Queen Elizabeth. It was rather fascinating.’ The ship, which cost its owners £473m to build, is the third P&O Cruises ship to be named Britannia but is easily the largest of the trio, with 15 passenger decks, 13 restaurants and four pools on-board. Britannia was also the name of the Queen's much-loved Royal Yacht which was decommissioned in 1997 under the orders of then Prime Minister Tony Blair. Berthed in Edinburgh's Port of Leith, the ship is now a static tourist attraction but sailed more than 1,000,000 miles during its 40 years in royal service. The new Britannia is expected to rack up a similar number of miles during its own career, although unlike the Queen's yacht, it will host tourists rather than dignitaries. Today, however, dignitaries were the order of the day for the new Britannia, with the Queen and the Duke of Edinburgh shown around the new ship by a large group of them. Isn't it magnificent? The Duke of Edinburgh and the Queen appear to be sharing their observations of the ship . Ready to launch: The Queen presses the button that will launch a bottle of fizz against the ship . Smashing! The Queen smashes a bottle of £24.95 English sparkling wine against the ship . Job done! The bottle of English sparkling wine smashes into hundreds of pieces . Celebration: Red white and blue confetti rains down on the Queen after the bottle is smashed . Sponsor: The Queen is all smiles as she becomes godmother to P&O Cruises' ship Britannia . Magnificent: Britannia is the newest P&O Cruises ship and can carry up to 3,600 people . Gargantuan: The vessel also boasts 15 passenger decks, 13 restaurants and four swimming pools . The Queen is no stranger to cruise ships in any case, having become godmother to no fewer than five - now six, including Britannia. First of the liners launched by the Queen was Cunard's QE2, which was christened in 1967 and made her maiden voyage in 1969. Now permanently moored in Dubai after retiring in 2008, its owners plan to turn it into a floating luxury hotel, although plans for the conversion are currently stalled. Other vessels launched by the Queen include the Oriana in 1995, the Queen Mary 2 in 2004 and Queen Elizabeth, another Cunard ship, in 2010. Well-wishers: The Queen was joined by Darcy Bussell, Anneka Rice and hairdresser Nicky Clarke . Supporter: Chef Marco Pierre White at the event. The P&O vessel features menus created by the famous chef . Enjoying the day:  Chef James Martin from Sunday Brunch with a friend at the event . Showing her support: Olympic Champion Sally Gunnell OBE made a rare public appearance at the reception . Royal salute: Comedian Rob Brydon salutes the captain while making a speech at the event . Hope his skills weren't needed! Retired swimming champion Mark Foster attended the event with a friend . Colourful: Entertainment was laid on for the guests, including professional dancers . Perfectly aligned: A marching band was also on hand to provide music . Spectacular scene: Hundreds of VIP guests were invited to watch the ceremony . Although the Queen is godmother to the largest number of vessels, she is not the only member of the royal family to have launched a cruise ship. In 2007, the Duchess of Cornwall launched Cunard's Queen Victoria at Southampton, returning five years later to blow out the candles on its fifth birthday in 2013. The same year saw the Duchess of Cambridge become a ship's godmother for the first time, with the royal, who was making her last public appearance before the birth of Prince George, invited to christen Princess Cruises' Royal Princess. The vast Royal Princess is one of the largest cruise ships ever built and has space for 3,600 guests, as well as an over-water 'Seawalk' which allows travellers to see what's going on below. Other vessels with royal connections include the Navy's new aircraft carrier, HMS Queen Elizabeth II, which was launched by Her Majesty in Rosyth with a bottle of whisky last year. The Duchess of Cornwall also has a naval vessel to her name, in her case the high-tech nuclear-powered submarine, HMS Astute. She is also the patron of a Cornish river ferry named the Duchess of Cornwall, which launched in 2008 and plies the waters between Falmouth and St Mawes. Launch: The Duchess of Cambridge has also played godmother to a ship, launching her first in June 2013 . Smashing! Her ship was Princess Cruises' gargantuan Royal Princess, which can carry up to 3,600 people . Royal approval: The Duchess of Cornwall sponsored Cunard's Queen Victoria, launching it in December 2007 .
The Queen has launched P&O Cruises new ship, Britannia . Her Majesty christened the ship with a £24.95 bottle of English wine . The Duke of Edinburgh joined the Queen for the ceremony in Southampton . He made the comment as his wife signed an empty picture mount . Britannia is the sixth cruise ship to be christened by Her Majesty . Camilla and Kate have both played the role of godmother to cruise ships . The royals have also sponsored several Royal Navy ships and submarines .