The only question - when will Tony leave?

The date of Tony Blair’s departure from Number 10 has become Britain’s key political issue. This is damaging and regrettable.

The facts are clear. Tony Blair has said he will not seek re-election and will give his successor time before the next election. Although the next General Election need not be till mid-2010, most people assume the Prime Minister means he will resign no later than mid-2008.

But when, exactly? This matters, and the Prime Minister cannot wish it away.

Strong government is about taking decisions that stick. Deciding policies that require new budgets, new arrangements and new laws. Whether it’s modernising the NHS, dealing with “problem families” [Blair’s latest concern] or reforming pensions, these are long term issues needing clear leadership.

You can’t give leadership if people think you are history.

Civil servants will wonder whether your policy may be altered within the year. Junior ministers will wonder whether they should be doing the bidding of the PM, or his likely successor.

And that person – the Chancellor of the Exchequer - is taking an extra year to decide on Government spending up to 2010 and beyond.

The stand-off is obvious. The smoldering feud between Blair and Brown is fast bringing sensible Government to a stand still.

The damage to Britain isn’t immediate. You won’t notice any difference this week. Yet as the number of decisions not taken mounts up, the size of future problems increases.