Cambridge is one of Labour’s more ambitious targets at the general election. The Liberal Democrats’ Julian Huppert won the seat in 2010 with a majority of 6,792 over the Tories, while Labour came a close third place. The constituency would need a mighty 8% swing to fall to Labour, but a recent poll conducted by Lord Ashcroft put the party ahead of the Lib Dems – albeit by just one point.

An illustration of Labour’s challenge to win Cambridge, and possibly a reflection on its current run of poor publicity, was provided by Thursday’s council by-elections. Labour not only failed to defend a seat on the city council, but also lost it to the Lib Dems:

The seat changed hands despite the result representing a swing from the Lib Dems to Labour of 3.6%. Note that Ukip didn’t bother to even contend the seat, although the party’s director of communications Patrick O’Flynn is a candidate here at the general election.

This nugget of pain for Labour is a reminder of how the collapse in Lib Dem support since 2010 suggested by national opinion polls is not consistent across the UK. Nor is it something Labour can take for granted as perhaps it once did.

Better news for Labour came in a contest for a seat on Dartford council, which it held comfortably and where Ukip were runners-up. This was just 10 miles along the coast from Rochester: site of next Thursday’s parliamentary by-election, which Ukip is expected to win. A second seat was also up for grabs on Dartford, but this was held by the Tories with Labour the runners-up and Ukip third.

The fact Ukip failed to take either of these seats may suggest a closer outcome than expected in the Rochester & Strood by-election. Alternatively it may be that most of the party’s resources are currently targeted in Rochester and spread rather thinly elsewhere.

One other seat changed hands in this week’s council contests. The Tories gained a seat from an independent on Wokingham council:

The seat had belonged to a Liberal Democrat who became an independent. Here Ukip managed only fourth place.

There were three other by-elections this week, but none saw any changes. The Conservatives held seats on Derbyshire and Mid-Sussex councils (though the latter saw a huge 20.8% swing from Tory to Ukip), and Labour held a seat on Wigan council.

The Press Association’s analysis of five comparable wards suggests a projected nationwide 1.1% Tory lead over Labour. Ukip averaged a 26.2% vote share in the six wards it fought.