(INFOSURHOY) -- The Prime Minister has saved British taxpayers tens of thousands by flying economy class for his Caribbean holiday with girlfriend Carrie Symonds. Boris Johnson touched down in St Lucia on Thursday morning after a long-haul British Airways flight from London. In a photograph taken by a fellow passenger, the Prime Minister can be seen at a window seat reading a book while Ms Symonds snuggles underneath her coat. The pair appear to be seated in economy towards the back of the plane, where passengers can often feel more turbulence than those at the front. A source told MailOnline that the couple kept a \u2018low profile\u2019 for the duration of the flight and were accompanied by \u2018little security\u2019. The cost of the flight would have cost in the region of \u00a31323 each, significantly less than if the Prime Minister had used an RAF private jet \u2013 which would more likely weigh in at around \u00a3100,000. It is understood the couple were not offered an upgrade on the flight due to strict anti-bribery and corruption rules in place at airlines. But Mr Johnson and Ms Symonds appeared happy to do their bit and save the taxpayer money ahead of their break in Mustique \u2013 their final destination \u2013 where they are staying in a luxury villa. Ms Symonds earlier this month proved herself a thrifty character after it was revealed she hired her designer outfits, rather than buying them outright. It also burnished her green credentials, in keeping with her day job as an adviser to environmental campaign group Oceana. Ecstatic British Airway crew squeezed around Mr Johnson and his St Lucian counterpart Allen Chastanet for a picture on the steps of the airplane after it touched down on Boxing Day. Mr Johnson also mustered a thumbs up as he wrapped an arm around Mr Chastanet, who congratulated him on his thumping election victory. Mr Chastanet said on Thursday: \u2018Today we welcomed British PM Boris Johnson to Saint Lucia for a short layover. \u2018I thanked the PM for his country\u2019s continued support to our country and the region and of course took the opportunity to once again offer my heartiest congratulations on his hard-won and well-deserved victory in the recent election. \u2018We look forward to working more closely together on our countries\u2019 shared mutual interests.\u2019 With a bag slung over his shoulder, the PM emerged from the plane wearing a dark suit jacket and trousers to meet the St Lucia leader. But he is expected to leave all formal government duties at the door of his \u00a320,000-a-week Caribbean villa where he and 31-year-old girlfriend will toast in the New Year and celebrate keeping the keys to Number 10. Mr Johnson and Ms Symonds \u2013 who was not pictured in St Lucia \u2013 are now understood to have arrived at Mustique to get some winter sun and relax after a tough month criss-crossing the country on the campaign trail. The couple, whose relationship has been under the spotlight since he became Tory leader in July, were hardly seen together during the election. In the aftermath of his win, Mr Johnson has still not had chance to put his feet up \u2013 instead ramming through his Queen\u2019s Speech bills and Brexit withdrawal deal. Yet, still flying high from storming to the largest Conservative majority since Margaret Thatcher, he and Ms Symonds will finally recharge their batteries on Mustique. Famed for its white-sand beaches, the exclusive island in the archipelago nation of St Vincent and the Grenadines is a favourite of the rich and famous, with Rolling Stones singer Mick Jagger owning property on the island. The extraordinary six-bedroom villa is perched on the hilltops of Mustique, giving resplendent views of the island. A brochure for the villa says: \u2018The open air plan provides the perfect balance of indoor and outdoor living spaces. \u2018Multiple sunset decks and lounge areas with seven lighted water features make the property well suited for entertaining. \u2018This tranquil villa rests harmoniously on a hilltop overlooking Britannia Bay, which offers perfect trade wind breezes and panoramic views of the surrounding Caribbean and lush landscape of the island.\u2019 The couple are understood to have landed at a nearby island yesterday, before taking another plane and arriving at Mustique today at the villa which boats three private pools, a butler, chef and housekeeper. The island is also a favourite of the Royal Family, with the Duke and Duchess of Cornwall having holidayed there as well as Princess Margaret who was gifted land on the island as a wedding present. She was famously photographed in 1976 with Roddy Llewellyn while still married to Lord Snowden, which caused a major royal scandal. In recent years, prime ministers have tended to take more low-key holidays with Theresa May enjoying walking holidays in Wales with husband Philip and David Cameron and his family often holidaying in Cornwall. But Mr Johnson is clearly in the mood for a more luxury retreat after securing his passage back to No10 with a thumping Tory majority.