gordon_brownGordon Brown may be a dead-man walking when it comes to domestic politics in the UK.

But the old man still believes he can pack a punch on the international scene, whether it be the financial or climate crisis.

Addressing the Major Economies Forum in London today, he used most undiplomatic language in predicting that the UK faces a “catastrophe” of floods, droughts and heatwaves if leaders fail to agree a deal at Copenhagen.

“In every era there are only one or two moments when nations come together and reach agreements that make history – because they change the course of history,” Mr Brown  has just told the delegates: “Copenhagen must be such a time.”

“If we do not reach a deal at this time, let us be in no doubt: once the damage from unchecked emissions growth is done, no retrospective global agreement, in some future period, can undo that choice,” he said: “This is the moment. Now is the time. For the planet there is no plan B.”

“In Britain we face the prospect of more frequent droughts and a rising wave of floods,” Mr Brown is expected to tell delegates.  The extraordinary summer heatwave of 2003 in Europe resulted in over 35,000 extra deaths.

“On current trends, such an event could become quite routine in Britain in just a few decades’ time. And within the lifetime of our children and grandchildren the intense temperatures of 2003 could become the average temperature experienced throughout much of Europe.”

“So we should never allow ourselves to lose sight of the catastrophe we face if present warming trends continue.”

Although the MEF is not part of the formal UN process, Brown’s blunt message will actually add pressure on him to help deliver a deal in Copenhagen, because he is advocating that world leaders must get personally involved .

“Agreement at Copenhagen is possible,” he finihed by saying “But we must frankly face the plain fact that our negotiators are not getting to agreement quickly enough. So I believe that leaders must engage directly to break the impasse.”

For Brown an agreement in December might not save him domestically but it certainly would help him when he faces the electorate next May.

There may not be a Plan B for him either.