Fraser, a barman at the Hootananny pub in Brixton, was last seen leaving the pub with two rucksacks containing his belongings on 8 June.
In a video recorded for Fraser, Leslie says: “It’s your birthday today but you have been missing since the 8th of June. Your friends and family are very worried about you so please get in touch. And a very happy birthday to you, wherever you are.”
Fraser is 5ft 10in (178cm) tall and has a slim build with brown hair and blue eyes.
His family have asked that he be approached gently as he may be suffering some mental distress.
His father Alastair said: “It’s very unlike him not to tell us where he is going. We’re worried about him and we’d like him to get in touch.”
Fraser’s family believe he may have travelled to one of his favourite photography spots in Kew Bridge, Richmond or Epping Forest, Essex.
Anyone with knowledge of Philippe’s whereabouts can contact police and quote missing person number 21MISO16978. His family can be reached at firstname.lastname@example.org.