If today ends up with the government in a row with the City over plans to tax bank bonus pots with bankers threatening to take the government to court, then it will be mission accomplished for the Labour party. The same goes if we end up in a debate over the merits of a Tobin-style tax. For obvious reasons, Labour would rather talk about anything other than the state of the public finances so anything that distracts attention from that central question is, to use the word of the morning, a bonus for Brown.
The Tories know this and will try and turn the debate back to the public finances and the fact that Britain was the first major economy into recession and is going to be the last out. It is imperative for them that they succeed. Their slippage in the polls is beginning to become a narrative in and of itself. If Labour gets through this PBR its supporters will go into the holiday season in good cheer while Tory mutterings and nervousness will start to rise almost as fast as the national debt.