But that could also be "Brown is twice as centrist as right's Cameron, say voters".
And most (boringly) accurately of all, perhaps "In crowded centre-ground, differences between the parties may begin to emerge", as a New York Times style headline might have put it.
For what the Populus figures show is this: a year ago, Gordon Brown was viewed a year ago by voters as 1.6% from dead centre, to the right; he is now seen as 4.2% from dead centre to its left (or alternatively 8% along a 0-5 scale from the centre to the left), while David Cameron is 8.8% away from the centre to the right (or 17.5% along the right-wing scale).
And the report does note this.
"However, Mr Brown is narrowly nearer both to the Centre and to the average voter than David Cameron, who is seen as shifting to the right".
The Labour Party is now viewed by most voters as just slightly to the left of the centre-point (at 4.82; which is 3.6% along the left scale) having been seen as just to the centre-right (at 5.20) a year ago.
Voters themselves have moved slightly leftwards, though they remain just to the right of the centre-line.
Tony Blair took pride in being seen by voters as being positioned exactly where they were themselves. It was a New Labour/New Democrat article of faith that the only way to win elections was to shadow the median voter, in the way that Downsian competition theory would predict. This was a successful strategy (particularly as Blair took good use of the opportunity to rhetorically occupy centre-right space left by an opposition happy to play to the right).
But this also had diminishing returns. Part of Brown's problem in rebuilding the Labour electoral coalition is that Labour voters perceive the government as right-of-centre, while most voters see it as centre or mildly centre-left. The swing voters are needed, but they are not enough on their own. And dead centre is much less effective strategy once the Conservative message is no longer "clear blue water" but "talk left and minimise the difference". If Labour can not persuade voters there is a difference between the parties, then we will find ourselves in the election David Cameron wants: a straight referendum on the government, in which the opposition escapes serious scrutiny.
This can seem a particular problem for left-of-centre governments: can they be both credible and idealistic, incumbent and insurgent? Yet it is interesting that the lessons of success in achieving this more often come from the right, which has frequently won elections with candidates who do not shadow the median voter - Reagan, Bush junior, Thatcher and John Howard.
The right often do this by reframing the debate - the culture wars, not the economy stupid, though this may (despite the Palin bounce) also bring diminishing returns in the US this time; and by prioritising an emotional and not just a rational appeal, as Drew Weston examines in The Political Brain.
Centre-left attempts to emulate this are rare. The fear is that these will always end in "no compromise with the electorate" defeat of a Michael Foot or George McGovern. And so the left is less good at tapping into core public intuitions around fairness and the responsibilities of government where the centre-left is much more on the popular side of the argument with the public than we tend to think, and framing public debates on our terms.
Yet one of the most interesting things about Barack Obama is that voters do not locate him at the dead centre of the political spectrum, as this Pew ideological perceptions graph from the primaries showed. (Democrats saw him fairly accurately as just left-of-centre, while Republicans thought he was out on the fringes).
For some that is his Achilees' heel. But his campaign also suggests where the way out of this apparent trap might be found: that the centre-left has not yet worked out how to combine a clear and confident articulation of its own values, which can mobilise support and enthusiasm, with an attractive pluralism in the way we do politics to have the breadth of appeal that any governing project needs.
Relatively centrist policy prescriptions and politics can sometimes (though not always) prove a more effective way to pursue egalitarian goals than tub-thumping. And social democrats are often straighter with the electorate than the right (which is often effective in mobilising anti-political sentiment) about what governing in the real world means. But centrism can not mobilise support without some clarity about the vision which underpins them.
There isn't going to be any lurch leftwards. But the tiniest of shuffles might even be worth the smallest of muted cheers.