The Liberal Democrats plan to rigidly focus their election campaign on ultra-local efforts in target seats, and worry less about getting a national narrative across, a decision that has caused disquiet at the party’s conference. The tactic, being finalised by party campaigners, would prioritise the “ground war” of mobilising supporters and bespoke messaging in a few dozen seats, at the expense of an “air war” to set out a broader vision for the party. As the party gathered in Bournemouth for what is likely to be its last autumn conference before the general election, some senior members told the Guardian they worried that this risked the Lib Dems slipping from the national focus. “People know that we’re against sewage and in favour of social care,” one said. “But that’s about it. You’ve got to wonder if it’s enough.” In media interviews on Sunday to mark the conference, the party leader, Ed Davey, was notably vague on policy specifics, refusing even to say that the Lib Dems want to ultimately rejoin the EU, something that is official policy. Some activists fear the Lib Dems could lose out electorally by not distinguishing the party enough from Labour, not just on Brexit but also areas like green subsidies and criminal justice. On Europe, the veteran pollster Prof John Curtice warned a Lib Dem conference fringe event that such caution risked losing votes among the very Labour supporters they need to attract to win more seats. “The Liberal Democrats have frankly lost ground among remain voters and the ground that they have gained among leave voters is not sufficient to compensate for it,” Curtice said. At another fringe event, Vince Cable said he believed Curtice was wrong on this point, but the former Lib Dem leader nonetheless urged a clearer approach to Brexit. “We must talk about it,” he said. “We must make it clear that we are a European party, that we identify with the European project and have a route map to get to the single market and the customs unions. We should talk about that and be proud of it.” However, party strategists are convinced that their tactic – an extension of the byelection methods that have seen the Lib Dems overturn four huge Conservative majorities since 2021 – will pay off. The party’s HQ has a constantly updated list of winnable seats, the bulk of which are currently Conservative-held, which are assessed on both local polling and the number of campaigners the Lib Dems will be able to send out. Many of these are based on the idea of the “blue wall”, traditionally Tory commuter belt and suburban seats, not just around London but also in places such as Greater Manchester and Yorkshire. As well as flooding the seats with activists, the election plan is to bombard voters with ultra-local messaging tailored to concerns raised by voters in the area, usually based around subjects such as the NHS or the environment. While the overall message is intended to be unified, party election planners accept that such a targeted approach will inevitably dilute the Lib Dems’ message on a national scale. “We understand as a third party, in a general election we are going to win MPs primarily on the strength of the campaign that we run in target seats on the ground,” one senior party source said. As to how many seats could be won, even privately Lib Dems planners refuse to speculate, still deeply bruised by briefings ahead of the 2019 election when they said the party could win 100 seats or more. It finished up with 11. “We’re in something of a bind,” another senior officials said. “We want to talk up our chances, but we can’t make it look like we’re being complacent or cocky.”