Prime Minister David Cameron is now on a charm offensive on two fronts as he works on a plan to get eurosceptic MPs behind his reform plans while trying to woo fellow European leaders.
Cameron is working on a plan to extend UK sovereignty, aimed at convincing sceptical Conservative MPs, including Boris Johnson, to get behind his deal.
The Major of London is thought to be a potential leader of the Out campaign, with sources close to Johnson saying his decision on which side to campaign on is "very finely balanced", according to the BBC.
The plan comes after the Prime Minister faced setbacks yesterday in his efforts to strike a deal with European leaders, with four eastern European nations raising red flags on the proposed welfare cuts and France thought to still be against financial regulation changes.
Cameron is hoping to get the unanimous backing of the other 27 EU member states at a European Council meeting in Brussels tomorrow, with a referendum expected to be held as early as June if he is successful.
Ministers are still unable to say which side of the referendum campaign they will be on, but it is speculated that if a deal is reached tomorrow they will be able to announce their allegiances on Friday.