British prime ministerial candidate Liam Fox said the principle of free movement of people should not be on the table in negotiations about a trade deal with the European Union following the country's referendum vote to leave the bloc. Former Defence Secretary Fox is one of five lawmakers competing to replace David Cameron as prime minister. Cameron said he would resign after losing June's referendum, handing over responsibility for complex negotiations with the EU, including on key issues such as trade and immigration, to his successor. "It is quite clear that the public rejected the concept of free movement, and that the price of including such free movement as part of a trade deal would be regarded as a betrayal by the British people," Fox said on Monday. Conservative lawmakers will gradually whittle down the five contenders to just two, starting on Tuesday, before grassroots party members vote by early September to decide the winner. Fox also said Britain should activate the formal 'Article 50' two-year EU withdrawal process by the end of the year, targeting a full exit from the bloc by Jan. 1 2019. "We cannot lose momentum and risk the derailing of the British people's decision by stealth. We need to recognise that we are likely to be frustrated by the ideological rigidity of the (EU) Commission," he said.