GB in many ways has been very unlucky, whereas Blair wasn't! The 'reins' were handed over to suit the former PM and things happened that GB had little control over. As 'Old Mac' said, "Events, dear boy, events".
This is not to say GB has been a good PM, but a bit harsh to attempt judgement at this stage.
There have been many unpopular Prime Ministers in my lifetime and various groups of the population may well have had good reason to dislike their choice.
Perhaps the current regime (including Blair) has been more open to the spotlight or has simply `spun` its way to unpopularity as a result of its actions.
There are major errors which, in my opinion, are unforgivable. These include the destruction of the company pension system, encouraging an economy based on consumer debt/spending and claiming the banking crisis was totally unpredictable. I think the average `man-in-the-street` could see errors in these if nothing else.
Given that Brown was involved directly in all of the above it certainly gives him support to be voted one of, or the, worst PM in modern times.
1. A decade as the chancellor, deciding fiscal policy has left him nowhere to run during a financial crisis. It very difficult to sack the person who left you open to failure when you are that person!
2. He isn't a good politician. He doesn't seem to be able to engage people. He simly talks and expects people to understand and believe.
His lifespan in office is getting shorter. There is no way that labour could win a general election with him as prime minister. The labour party should oust him well before the next general election, but I suspect that he thinks that the public's opinion can be changed by a few weeks of campaigning. How wrong he is.....
I don't blame him the financial crisis, but i can most definitely blame him for leaving the country prone to it's effects, and the actions he took to 'relieve' it's effects.
Really my point was that if roles were changed and there was a different chancellor, politically it would have been easier for him. Sack the chancellor, appoint a new one in a load of spun hype and distract the public from the truth. Politics at it's best ;)