It is 3.30pm on Tuesday. Madam Speaker calls the House of Commons to order, and a rare silence falls over the chamber. You rise to your feet, sip delicately from the crystal tumbler of 20-year-old malt whisky poised on the despatch box in front of you, and begin to deliver your Budget speech.

What would you have said that Gordon Brown didn't? How would you have juggled direct and indirect tax rates, thresholds, allowances and benefits? And what would the effect on the national finances have been? If you think you could do better than the chancellor, BBC Budget 98 is the place to go.

This year, the Beeb has taken over the interactive model developed by the Institute for Fiscal Studies and added it to an impressive array of other goodies. If your interests lie more in the direction of the effect on your own pocket, there is a model for that too.

In the run-up to the Big Day, the BBC called in its big name economics and politics pundits to outline the options for what one dubbed the Titanic Budget ('women and children first'). There is also some good background information: longest and shortest speeches, chancellors' favourite tipples, and so on.

The advantage a broadcaster has is access to an extensive sound and video archive, which is used to effect here: when Budget 98 tells you about interruptions to chancellors' speeches, there are tapes of, for example, the uproar which ensued when Nigel Lawson cut the top tax rate to 40 per cent.

But ultimately, if you want to make serious use of this site there are problems: the interactive model assumes that changes to tax rates have no impact on consumption, so you don't know whether doubling cigarette duties cuts sales. Anyone up to developing a more comprehensive model for Budget 99?