Today's embarrassing reversal by the Office of Fair Trading is the first major one for John Fingleton, a man accused of academic arrogance and populist consumerism, and of being too eager to get his hands on the big companies.

Fingleton, 42, caused a storm at the OFT, arriving from the Irish Competition Authority in 2005 via at least five universities, training as an economist. He immediately promised to drop a third of the agency's caseload to concentrate on major issues and major companies, and the headlines have rolled.

The OFT has grandstanded over Sky's controversial 17.9% stake in ITV, price-fixing at British Airways and drugs cartels in the NHS. Hardly a week goes by without Fingleton's work appearing in the financial pages.

In the past week, his clampdown on a cartel of construction firms headed by Balfour Beatty saw 112 businesses fingered in what is thought to be the most wide-ranging investigation yet by the OFT.

Only yesterday, BAA's monopoly of London airports was harangued by the Competition Commission. That case was launched by Fingleton two years ago and was seen as signalling the iconoclasm of the Irishman as competition regimes and transport ministers had been happy to let pass the fact that Heathrow, Gatwick and Stansted control 92% of London's air passengers. Tomorrow will see the results of Fingleton's latest attack on the banks.

The accusation against Fingleton is he is pursuing consumer rather than competition policy, that his version of customer protection takes precedence over fair trade enforcement.

He insists one doesn't exist without the other. "We are not Which? or the Citizens Advice Bureau," he says. "Our brief is to look at whether markets are working well and deliver the best possible outcome for consumers."

Morrisons may argue: "And treat business fairly too."