BRUSSELS, Rabi'I 6, 1437, Dec 17, 2015, SPA -- Prime Minister David Cameron took the floor at a European Union summit on Thursday to try to persuade fellow leaders to give Britain improved membership terms, including disputed relief from immigration, before it votes on staying in the bloc, Reuters reported. EU officials said Cameron began his pitch after European Council President Donald Tusk told the summit there was good progress on three of London's four key demands, but the fourth - to deny EU migrants in-work benefits for four years - was "very difficult". Other leaders around the dinner table want to help Cameron ensure Britain chooses to stay in the EU in a referendum due within two years, with opinion polls showing the number of Britons wishing to leave is growing. -- SPA 02:16 LOCAL TIME 23:16 GMT www.spa.gov.sa/w