New Leader	Pre-election ICM	Post-election ICM	Uplift
John Smith 1992	35	39.33	4.33
Tony Blair 1994	44.66	47.66	3
William Hague 1997	31.4 (GE result)	25	-6.4
Iain Duncan Smith 2001	29.66	29	-0.66
Michael Howard 2003	32.66	33.33	0.66
David Cameron 2005	37.33	39.33	2
Gordon Brown 2007	31	39	8
Mili-E/Mili-D 2010	??	??	?

What’ll be the scale of the new leader bounce?

If the next election is fought on the current boundaries then the uniform swing projections suggest that Labour needs a lead of less than three points in the GB vote to secure an overall majority.

Given that it’s widely expected that the red team will get a poll bounce following the election of their new leader on September 25th should we expect the October polls to be suggesting a margin of that size.

Certainly based on historical poll moves when new Labour leaders have been elected then a margin of three points or more is possible – but only just given they are four or five points behind at the moment. There’ll be masses of publicity for the new man in the final few days of September when, of course, it’s Labour conference time.

The above table seeks to show what happened to the Tories and Labour in ICM Guardian polls in the first three months of a new leader compared with the ratings in the previous three months. For William Hague in 1997 I’ve taken the election outcome for as the point of comparison.

A lot here depends on what else is going on and poor Iain Duncan Smith started his period as Tory leader almost immediately after the attacks on the Twin Towers and the Pentagon on September 11th 2001.

All but Gordon Brown on the list became opposition leader on becoming party leader. Brown was, of course, prime minister.

The table shows a marked difference between new Tory leaders and Labour ones. The former, even Cameron, got small bounces while the Labour ones fared better. Will that happen to Labour under DM or EM from September 25th onwards?

In the last ICM poll at the end of July it was C38-L34-LD19.

Mike Smithson