Whatever the reason, it's a welcome change of mind. As Cameron has said, the British people deserve to see the two of them up close and personal during an election campaign. It's not being presidential, it's just the way our politics are done nowadays. I suspect such a debate would get a massive audience and would hopefully really catch the imagination.
Many commentators automatically assume that Cameron would walk such a debate. Don't be so hasty. They are risky things, as I well remember from the leadership contest. In the Question Time debate, David Davis was a clear winner, and the others were draws. Nothing should be taken for granted, as Brown is likely to come out fighting.
Bring it on!
UPDATE: According to The Times, Gordon Brown has firmly shut the door and slapped down our very dear First Secretary of State. Does Mandelson feel so powerful now that he feels he can just freelance on issues like this without even having discussed it with the man formerly known as the Prime Minister?
UPDATE 6pm: David Cameron has written to Gordon Brown...
I am writing to ask you to clarify the Government’s position on the issue of a television debate between the leaders of the main political parties.
Five months ago, when I challenged you at Prime Minister’s Questions to a televised studio debate, you refused. This morning, Lord Mandelson said you were open to the idea. But within an hour, a Downing Street spokesperson back-tracked, saying this was not the case.
The Government seems to have a number of positions on this. I’ve only ever had one: a prime time televised debate is just what our political system needs.
It would help to energise our democratic process, engage the electorate and restore trust in politics. Democracies across the world – from Australia to America to Brazil to Indonesia – have benefited from the invigorating effects of these debates. Even in Iran a series of television debates was held during the recent election campaign.
Your previous objection was that a televised debate was unnecessary as the issues were aired each week in parliament. But Prime Minister’s Questions simply cannot compete with the accessibility of a primetime studio debate. I want the chance to set out the choice at the next election to many more people than those who watch on a Wednesday lunchtime.
For these reasons I hope you will today make clear your position on this crucial issue.