It looked significant at the time but in retrospect the 2010 tie-up between Lovells and Hogan & Hartson genuinely marked – and itself influenced – the changing shape of the legal industry. Not only because it constituted a transatlantic union between two major firms, but because the pair chose to deploy a multi-profit centre structure that has since been widely used over the last two years.

Some deals haven't dazzled but none looks more significant than last week's news that Norton Rose has secured a tie-up with Fulbright & Jaworski. But then arguably it was Norton Rose that created the model for Hogan Lovells with its takeover of Deacons. Rivals scoffed but it kicked off a run of deals in Australia by firms that see themselves as well above Norton Rose's station.

The underlying point? The Fulbright deal highlights the extent to which the last five years have seen industry-defining activity occurring outside the magic circle. Of course, claims that London's legal elite would wither in the face of recession were nonsense but, as a group, neither have they displayed quite the dominance we've come to expect, as we address in this week's analysis on Linklaters.

There is a certain amount of denial about this but on a neutral reading Norton Rose, Hogan Lovells and DLA Piper all look capable of becoming realistic threats, at least for the more price-sensitive work that still makes up a lot of magic circle business.

Around 2008-09 there was a well-judged shift at the top firms to focus on quality after a period of expansion, but I'd argue Linklaters and Freshfields are now in danger of over-correction. And you've only got to look at the progress made over the last five years by Norton Rose to see how much the market has shifted

Also significant is the dramatic rise of the expansive Allen & Overy, a firm that wasn't that long ago being written off by some as a magic circle player. Just hunkering down doesn't look much of an option.

It's absolutely right to assert that huge pressure is now on firms like Norton Rose to make these deals deliver, but there's no guarantee for more prestigious rivals that they'll fail. Call me old fashioned: I like my market leaders to achieve domination through shock and awe superiority, not quietly hoping potential challengers screw it up.

And even if Norton Rose Fulbright falters in execution, there will be other global pretenders, be they DLA Piper, Latham & Watkins, King & Wood Mallesons or something more disruptive. When you're the best, challenges come on many fronts.

As a breed, the magic circle has been a great advert for British business and they'll likely get back on form, but that's more likely to happen when they accept they are less untouchable than in the boom years. After all, no one ever went out of business by over-estimating the competition.