Elections 15 June 2018 Why are the Liberal Democrats celebrating defeat in Lewisham East? Lessons from a landslide. Getty Vince Cable and defeated Liberal Democrat candidate Lucy Salek. Sign UpGet the New Statesman's Morning Call email. Sign-up Triumphant defeat? The Liberal Democrats are cock-a-hoop after finishing second in the Lewisham East by-election, where they increased their share of the vote from just 4.4 per cent in the general election to 24.6 per cent in the by-election. They also increased their raw vote by more than 100 per cent, going from just under 2,000 votes to just over 5,000 votes. It was the biggest Labour to Liberal Democrat swing since the Brent East by-election in 2004, when Labour had been in office for seven years and during the height of the Iraq war, and their best performance against another opposition party since 1983. But they finished 25 points behind Labour in a constituency that, while being less Remain-heavy than its neighbours, is still more pro-European and therefore you’d assume more fertile territory for them than the average constituency. In addition, the Liberal Democrats tend to do better at by-elections than general elections, because at by-elections, their main problem – that voters fear they are a wasted vote – isn’t as acute, as the worst that happens if you waste your vote in a by-election is that your MP is of a party you don’t like, whereas the worst that happens if you waste your vote in a general election is that your government is of a party you don’t like. So I wouldn’t, on this showing, say the Liberal Democrats were presently on a trajectory to take Labour seats at the next election. (With the exception of Sheffield Hallam, where there are important local factors at play.) So why are the Liberal Democrats so happy? Well, firstly because while they can’t gain Labour seats at a general election on performances like this, they can gain Labour seats at by-elections and local elections, which adds to their perceived viability which does help at general elections. The second reason links into one of the reasons why the other political parties are very envious of the Liberal Democrat by-election machine: the Liberal Democrats have many more opportunities to safely test out their campaign messaging in the field than the other political parties do. If you are either of the big two, you compete for power across the country and you don’t have many contests where you can try things just on the off-chance that they work, and in the seats that you do, they don’t tell you a great deal. (You can, for example, roll out your new campaigning software in your very safe Conservative seat but it may then struggle to manage homes of multiple occupancy in the Labour marginal down the road.) Whereas the opportunities to battle-test your campaign techniques when you are a party that even at its peak has only ever had 100 realistic targets is a lot higher. The Liberal Democrats believe they’ve learned a lot about how to win over Labour Remainers, something that they knew before Lewisham they struggled to do. They now think they’ve hit on two strong messages. The first is that Labour Remainers are receptive to the idea of “sending a message” to Jeremy Corbyn but don’t respond well to direct attacks on the Labour leader. The second is that they do respond well to messages about living “in a one party state” and providing an opposition to the local council (which in many former Labour-Liberal Democrat battlegrounds are now entirely Labour-run). But the problem for the Liberal Democrats is that these messages are both a lot more effective in local contests and by-elections – you cannot “send a message” to the opposition in a general election – than they will be next time the country votes for a goverment. › Today’s report on Universal Credit is hardly surprising. But the failing system can still be fixed Stephen Bush is political editor of the New Statesman. His daily briefing, Morning Call, provides a quick and essential guide to domestic and global politics. Subscribe For more great writing from our award-winning journalists subscribe for just £1 per month!