Britain could leave the European Union as early as next year as Prime Minister David Cameron is said to be already putting plans in motion to bring forward an in/out referendum by a year. If Britons vote to leave the EU, this means the country could technically start severing its ties by the end of 2016. The Conservatives won Thursday's General Election with a 12-seat majority. The Tories will have to deliver a referendum by 2017 over whether Britain will stay part of the EU, as it was a linchpin pledge during the campaign. According to The Guardian, which cited unnamed government sources, Cameron is keen to move the referendum forward to capitalise on Tory support and to avoid being caught up in the French and German elections in 2017. "The mood now is definitely to accelerate the process and give us the option of holding the referendum in 2016," one of The Guardian's sources said. "We had always said that 2017 was a deadline rather than a fixed date." Another source said: "It was made pretty clear that the European Council [the grouping of the EU's 28 leaders] would not engage seriously until the election result was clear. Now they know they have to deal with us and they want the UK to stay in the EU. "We expect the negotiations to take place in 2015 and 2016 so they finish well ahead of the French presidential elections [in spring 2017] and the German federal elections [in September 2017]." EU referendum pressure The Conservatives are under pressure to hold an EU referendum amid growing disdain for the 28-member bloc's influence over the UK. In an ING analyst note this week, the group highlighted how the latest Eurobarometer public opinion survey showed just 23% of Britons had a "generally positive" view of the EU, with only Greece having a lower rating (22%). Couple this with the 3.8 million people who voted for the UK Independence Party, which is opposed to staying in the union, and the number of Eurosceptics from other political factions and it could be a very real threat to Britain's EU membership. Though the Tories are pushing through the promise of a referendum, however, the party is largely against leaving the EU. In January last year, UK Chancellor George Osborne said the Tories were determined to deliver on the promise of a referendum but they would prefer to stay within the EU and negotiate "a better deal." "Our determination is clear: to deliver the reform and then let the people decide," Osborne said in a speech at a Tory party conference on January 14. "It is the status quo which condemns the people of Europe to an ongoing economic crisis and continuing decline. And so there is a simple choice for Europe: reform or decline."Join the conversation about this story » NOW WATCH: 'Game of Thrones': The Iron Throne is a terrible investment