It was a relief to hear Gordon Brown declare in his speech about immigration that he would not allow people to "scaremonger" on the subject.
The Prime Minister rightly pointed to figures showing that net migration has fallen significantly since 2007. As the graph below shows, net migration fell from 233,000 in 2007 to 163,000 in 2008.
Official figures for 2009 have not been published, but early indications suggest that there has been a further fall to 147,000. The recession prompted many east European migrants to return home and the overall number migrating from Britain has reached a 17-year high of more than 400,000.
Despite this trend, the Tories remain committed to their absurd plan to place an annual limit on immigration. David Cameron has promised to reduce net migration to "tens of thousands" per year, a level not seen since the days of the Major government. But as Brown rightly argued, this populist policy is "arbitrary and unworkable".
For a start, Cameron cannot limit immigration from within the European Union without restricting the free movement of labour and throwing the UK's continued membership into doubt. His policy also ignores the 39,000 people who come to the UK on spousal visas after marrying British citizens abroad.
No party can afford not to make immigration a central issue at the election. A recent YouGov poll of 57 marginal seats found that only the economy matters more to voters in these areas.
The poll also found that 44 per cent of respondents in Labour-held marginals would be more likely (23 per cent much more likely) to vote Tory if Cameron pledged to reduce net migration to 50,000 a year.
But if Labour exposes Cameron's pledge for the hollow promise that it is, it need not lose any votes over the subject.