First a series of changes to the format of a race weekend were introduced late last year - and now there have been more radical modifications to the technical rules.

This is a guide to what has been done so far, as well as what may still change in the future.

1. Banned immediately
2. Banned from British GP
3. Banned from next year
4. Differences from first draft of changes
5. Still under discussion
6. Race weekends

Banned immediately

Pit-to-car telemetry
Systems that allow teams to make changes to their cars' settings while they are out on the track have been outlawed after being legalised only in May 2001.

This will make it harder for teams to prevent cars breaking down if they develop problems in their engines, gearboxes or systems during a race.

Qualifying cars
A rule has been introduced to prevent teams building special cars at enormous cost for the new one-lap qualifying runs.

Cars will now be impounded by race officials immediately after qualifying and teams will not be allowed to work on them until just before the race.

This prevents the design of cars with special features that would not last a race distance but would be much quicker in qualifying.

Banned from British GP 2003

Electronic "driver aids"
Systems that take away control of the car from the driver will be outlawed in another volte face from May 2001.

This includes: traction control, which prevents wheelspin under acceleration; launch control, which guarantees a perfect start every time; and fully automatic gearboxes.

Semi-automatic gearboxes will still be allowed.

These systems were legalised in May 2001 after complaints that teams were getting away with cheating because F1's governing body, the FIA, could not police them.

Now the FIA is developing software that it believes will be able to detect these systems if they are being used.

Banned from 2004

Car-to-pit telemetry
Systems that transfer data from the car back to the pits, enabling engineers to tell what is going on inside its systems, are banned from next season.

This is a progression of the ban on pit-to-car telemetry, but is more controversial as it is simpler technology and has been in use for much longer.

It will further reduce the ability of teams to step in to prevent problems becoming terminal.

Differences from first draft of changes

Spare cars had been banned altogether - but these will now be allowed if a driver damages his race car beyond repair during practice or qualifying.

Radio links between the pits and the drivers will now be allowed, having initially been banned.

Still under discussion

Engine restrictions are the most controversial of all the changes because many of the car manufacturers in F1 do not want there to be any.

As of today, the only rule on this is a restriction of one engine per race weekend from the start of the 2004 season.

Beyond that, there has been no agreement, although the FIA has suggested limiting teams to six engines for a season.

There is also a drive to force manufacturers to supply engines to a second team.

This is likely to be introduced after Mercedes, previously the most vociferous opponent, said it would be happy to agree.

To ease teams' financial problems, this may be extended to allow smaller teams to buy other parts - like chassis and gearboxes - off bigger ones.

Race weekends

The changes to the format of race weekends announced in October 2002 stay in place.

That means the following:

• Drivers will have only one lap to determine their grid position. A session on Friday will determine the order for the Saturday session which will define grid positions for the race.

• Teams will have to start the race with the same fuel load that they use in qualifying. That could lead to huge variations in grids as some smaller teams sacrifice race performance in favour of the profile afforded to the front of the grid.
  

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• The points system has been changed. The winner will still get 10 points, but drivers down to eighth place will now score points in a system that goes 10-8-6-5-4-3-2-1.

• Team orders have been banned

• Teams can sign up for extra running at race weekends if they agree to limit their testing to 10 days during the season.

• Tyre manufacturers can now custom-make tyres for each of their teams, as opposed to only two types of tyres for all their teams.