Cameron said after an EU summit in Brussels that his government aimed to achieve a breakthrough at the next summit in February in his drive to reform the 28-nation bloc, and then encourage British voters to remain inside.
"I believe that 2016 will be the year we achieve something really vital, fundamentally changing the UK's relationship with the EU and finally addressing the concerns of the British people about our membership," he told a press conference, at the end of a two-day summit dominated by the migrant crisis and efforts to avoid a so-called Brexit.
A law being passed by the British parliament stipulates that the referendum must be held by the end of 2017, but Cameron has not set a date. Reports have suggested he is keen on mid-2016, as soon as possible after a deal.
Yesterday, Cameron hailed "good progress" toward a reform deal with his European Union peers but warned there would be hard work to seal an accord by February as hoped.
Also Read
Cameron appealed to his EU colleagues to work with him on his demands -- which include a controversial proposal to ban EU migrants from receiving government handouts for their first four years in Britain -- before he holds his referendum on a possible "Brexit".
He urged them to "work together to fix" the bloc.
Cameron's other demands are for Brussels to ensure greater protection for non-eurozone member states, an exemption from the EU's goal of "ever closer union", and greater economic competitiveness, but these three issues are much less controversial than his migrant welfare limit.
EU president Donald Tusk said last night that the leaders had agreed to work towards a compromise, including on the controversial migration issue.