Sunday sees three polls published. ICM gives a Labour lead of 4% and YouGov suggests a Labour lead of 2%. Both of them suggested virtually no change from the start of the campaign last week.
However, Mori showed a Labour lead of 7%, compared with a Conservative lead of 5% which they registered in the previous week.
Mori's voting intention is drawn from only those respondents who say they are absolutely certain to vote.
This significant shift may be the result of a stiffening of intention to vote among Labour's supporters.
Labour would like to think so but we should look for more supporting evidence before we risk suggesting that the election campaign has shifted decisively Labour's way.
Earlier campaign polls suggested that the issues of asylum and immigration have risen in public consciousness but we have little evidence yet that this will deliver decisive votes to the Conservatives.
There is general grumpiness about public service provision but on the economy, broadly two out of three people consider it a success.
In the past such public ratings of economic success would have been regarded as confirmation of a clear government victory.
Labour's apparent difficulty in translating these positive feelings into decisive electoral support is a weakness in their campaign so far.
One distinctive feature of the polls to date is how the Conservative share is, generally, little higher than the 33% of the vote they secured in 2001. Wherever Labour's past voters are going, they are not shifting in large numbers to the Conservatives.
The Lib Dems seem to be retaining the relatively high level of support they have enjoyed since the last election.
However, their hope that, as in past elections they pick up significant support during the campaign has yet to be realised.
The Pope's death and the Royal marriage have brought about a truce in campaigning for a few days. The next set of polls may tell us whether this break in momentum has damaged the prospects of any of the parties.