Clegg and the capital

I was surprised by the size of the Clegg Effect. That might be partly because the lack of a TV signal in the corner of Cornwall where I and my family stayed throughout last week meant that, unlike most fellow voters, I heard the first leaders' debate on the radio rather than watching it on a screen, which seems to have suited the Lib Dem leader's style so well. The Clegg Effect is clearly real, but to what extent will it translate into votes and seats? That's very hard to say. But if it retains significant force until polling day it could have a big impact in London.

The last leg off my long drive home yesterday took me through the constituency of Islington South and Finsbury, where the Lib Dems' Bridget Fox has high hopes of replacing Labour's Emily Thornberry. These have surely received a huge boost, while Tory designs on Lib Dem strongholds in the capital's Surrey-ish south-west will have taken a blow. Crossing the Chiswick flyover I could almost hear Lib Dem MPs Susan Kramer (battling Zak Goldsmith in Richmond Park), Tom Brake (Carshalton and Wallington) and Paul Burstow (Sutton and Cheam) still cheering Thursday night's performance by their leader. Ed Davey in next door Kingston and Surbiton will feel still more confident of seeing off any Conservative revival, as will fellow incumbent Lynne Featherstone from any Labour comeback in Hornsey and Wood Green.

Meanwhile, Sarah Teather (Brent Central) and Ed Fordham (Hampstead and Kilburn will feel empowered in their battles against Labour rivals. Already you can see that a sustained Clegg Effect in London would damage both larger parties, and maybe do so roughly equally. Perhaps the best place to judge if it is hurting one more than the other would be Brentford and Isleworth, where Labour's Ann Keen's troubles over expenses have turned her seat into something of a three-way marginal and number 64 on both the Tories' and the Lib Dems' target lists.

Where London is concerned, the clearest consequence of Nick Clegg's win in the first debate has been to make it less clear how London will swing. With the Labour vote apparently holding up in strongholds elsewhere in Britain, the Conservatives will be frantic to make big gains here. A You Gov poll of London voters taken at the end of last month showed an eight percent swing towards them away from Labour, but any substantial general increase in support for Liberal Democrats come polling day will increase to the number of seats where tactical voting could come into play. Throw in a wide range of local factors and the potential for volatility and unpredictability goes up again. I anticipate the Clegg Effect diminishing over the remainder of the campaign, but in London as elsewhere it has already changed the game.