Surrey, the hosts of next year's tournament, have benefited from the competitive attitude that the Twenty20 Cup has fostered © Getty Images

Expansion was inevitable. And, after the phenomenal interest that has been generated over the past two seasons, it was quite welcome as well. But the England & Wales Cricket Board, which deserves great credit for pioneering the concept of Twenty20 cricket, is in danger of overcomplicating a simple format, judging by the puzzling mathematics that have been called upon for next year's tournament.

On the face of it, there is little cause for complaint about the proposed schedule for next season. Instead of five first-round matches per county, that number has been bumped up to eight (four home, four away), which means that, for the first time, those counties with famous local rivalries - Lancashire and Yorkshire, Surrey and Middlesex, Warwickshire and Worcestershire - will each enjoy the prestige (and gate receipts) of a home derby match.

So far, so tasteful. That hardly represents the all-encompassing expansion that might have been envisaged, although it is clearly a move that is geared towards maximising the mid-season windfall that county cricket has suddenly hit upon. The decision to hold next year's finals at the newly revamped Oval will also get the cash registers ringing. By 2005, The Oval's long-overdue makeover will be complete, and with a capacity of 23,000, it will be more than a match for Trent Bridge and Edgbaston, the previous venues for the finals.

One thing doesn't quite add up, however, and that is the numbers involved. The five-match format was a thing of mathematical simplicity, as the 18 counties divided snugly into three pools of six teams. Four home matches and four away, however, rather suggests that we are to expect pools of five next year.

But five into 18 doesn't quite go, so the exciting conclusion to be drawn is that the ECB intends to introduce two new teams to make up the numbers - Scotland and Holland, perhaps? Not so, according to one of their spokesmen, who ruled out such a possibility for several years to come. Instead, it was suggested that "some teams might play fewer games than others" - the "some", one would imagine, would be those mateless, moneyless paupers who have no natural rivals, and less pulling power than those eager punters who flocked to Warwickshire's speed-dating stalls this season.

It is not quite commercialism gone bonkers, but it is certainly an unwelcome step in the wrong direction. The Twenty20 Cup may be steeped in gimmickry, but at the heart of the concept is a lively and highly competitive form of the game. Robert Croft, whose Glamorgan Dragons were on fire in the regional rounds, said that the teams' intensity had gone up a notch after realising that this was not some "mid-season charity bash".

The Twenty20 Cup doesn't deserve to be treated merely as a cash-cow, but more importantly, it will benefit no-one - fans, teams and county treasurers - if it is. The ECB is not exactly cooking the golden goose just yet, but it does seem intent on plucking a few tail-feathers.