The latest ICM poll for The Guardian is published today. Its topline figures show Labour on 35% (-2%), the Tories on 32% (n/c), with the Lib Dems on 14% (+2%) and Ukip on 10% (+1%).

The changes from last month are all within the margin of error, so nothing too dramatic can be read into it. The ratings are mildly encouraging for the Lib Dems. The ICM poll at the equivalent point in the parliamentary cycle – January 2009 – had the party at 16%. ICM’s poll is the one most eagerly awaited by poll-watchers, as the company has the best historic track record. It also tends to give the Lib Dems better ratings (than, say, YouGov) because of its methodology – but it’s a methodology which has yet to be tested under Coalition conditions.

Input the figures into Electoral Calculus’s online prediction software and you’ll see they’d give Labour a majority of 24, with the Lib Dems reduced to 35 seats. In reality, I think the Lib Dems would do a little better than that on 14%, owing to the incumbency boost of our MPs’ (and local activists’) hard work – which would also likely eat into Labour’s seat tally, as it’s the Lib Dem-Labour battlegrounds where we’re most vulnerable.

The Tories’ stagnant ratings will trouble the party given the poll’s finding that economic optimism is definitely on the up: ‘a narrow majority of 52% of voters are now confident about their own financial position, and “ability to keep up with the cost of living”, the highest score on this question since October 2010?.

Conventionally, you’d expect this to boost the governing party’s (or, in the case of the Coalition, parties’) poll ratings. Yet its only apparent effect this month has been to subdue Labour’s ratings. The reason why not is presumably Ukip’s strong showing, driven in large part by immigration concerns. ICM’s findings are interesting:

Younger voters are much more evenly split on the immigration question, but there are two segments of the electorate where opinion is completely out of kilter with the rest. First, professionals, in the so-called AB occupational grades, who by 50% to 35%, say migration has been good for the country. Secondly, Ukip supporters, who – by a crushing majority of 91% to just 2% – take the opposite view, and insist that the effect is to take jobs and depress pay.

That younger, professional voters – mainstays of Lib Dem support – are least likely to buy the immigrant myths of the media (and politicians) will hopefully encourage the party leadership to stick to a principled line that recognises the benefits of free movement of people.

* Stephen Tall is Co-Editor of Liberal Democrat Voice, and editor of the 2013 publication, The Coalition and Beyond: Liberal Reforms for the Decade Ahead. He is also a Research Associate for the liberal think-tank CentreForum and writes at his own site, The Collected Stephen Tall.