THE starting gun for the referendum on whether Britain should leave the European Union has yet to be fired. But David Cameron has made clear that he expects to finish renegotiating his set of EU reforms in Brussels by the end of February. Since the referendum act provides for a minimum four-month campaign, some say that the vote could now take place before the end of June—though insiders think late September is still more likely.

Either way, the pro and anti campaigns are gearing up, starting by raising cash. It is up to the Electoral Commission to designate, for each side, a lead organisation that gets extra money, free leafleting and broadcasting rights in exchange for strict spending limits. The choice is clearer on the Remain side: it will be Britain Stronger in Europe, chaired by Lord Rose, a former boss of the Marks and Spencer retail chain. Its director, Will Straw, says it is a broad cross-party group akin to the Better Together group that won the 2014 referendum on Scottish independence, but intent on making a more positive and patriotic case.

Britain Stronger in Europe had a shaky start, but now looks more effective. Yet it still seems outgunned by its opponents, who have a simple and seductive message about escaping Europe’s chronic mess. This may be why the polls have narrowed (see chart). Alan Johnson, who runs the Labour Party’s In campaign, laments that, although his side has the best lyrics, his opponents have the best tunes. Yet the Leave campaign has problems of its own—starting with the fact that it is divided.

Leave.eu, financed by Arron Banks, a businessman, is closely linked to the UK Independence Party’s leader, Nigel Farage, and focuses on immigration. Vote Leave, run by Matthew Elliott, is broader based, and includes UKIP’s sole MP, Douglas Carswell, as well as members of other parties. It seems more likely to win official designation, not least because Mr Elliott and his colleague, Dominic Cummings, are veterans of previous successful campaigns, including the defeat of a referendum on electoral reform in 2011 and of plans for a North-East regional assembly in 2004.

Both sides are keen to draw lessons from previous referendums in Britain and from other countries. Among them are the view that it is important to start early; that basic concerns such as jobs and the economy weigh heavily; that there is a bias in favour of the status quo; and that, although negative messages about the other side can work, they need to be supplemented by positive ones. In the EU case, Mr Cameron’s renegotiation will count for little but his (and his government’s) view will count for a lot. And ever present is the risk of a vote being hijacked by unrelated issues.

Most of these lessons ought to favour the Remain side. The main business and trade union organisations support Britain’s EU membership on economic grounds, as does most of the British establishment. The status quo or inertia vote will lean towards staying in, though on this Vote Leave is trying to argue that, since the EU is changing so fast and moving inexorably towards closer political union, the real status quo vote should be one to leave.

Similarly, a negative message is harder for Vote Leave to fend off. As in Scotland, it is vulnerable to the charge that it is not offering a clearly thought-through alternative to EU membership. Would Britain keep full access to the single market, which takes almost half its exports? Might it, like Norway and Switzerland, have to accept most EU rules and even pay money to Brussels in return? The Leave campaign insists that, as a big economy and large market for other EU members, Britain would secure a favourable deal, but it remains vulnerable on the question of alternatives.