British police interview returning tourists of Tunisia attack Prime Minister David Cameron warns Britain to prepare for further casualties from the attack on a Tunisian beach resort -- already the worst loss of British life in a terror incident since the 2005 London bombings. British police are interviewing many of the returning tourists, in particular looking for any footage taken on mobile phones of the incident, and have also sent forensic experts and detectives to Tunisia to help gather evidence. IMAGES AND SOUNDBITES of Scotland Yard