This poll result is phenomenal:

YouGov asked voters who they would choose from a list of politicians “at the peak of their powers” to be prime minister. Maggie Thatcher was the most popular with 27% wanting her back.

Brown was unpopular even among Labour voters: 43% of whom wanted Blair back, even Tony Benn was wanted by 17% of the party’s voters, Brown was the first choice of only 10% of Labour voters.

UPDATE : Guido forgot to quote the most important statistic, a mere 5% of all voters would rather have Gordon Brown as PM from the list of former PMs given.