For most UK firms the market is looking considerably rosier today than it was back in December 2004. But partners at Pinsent Masons will always look back on that time with a certain amount of fondness. For that was when Pinsents sealed its merger with Masons.

The market may have been sceptical about the deal, but for the firms involved it held up the possibility of a dramatic change in their fortunes, by allowing two sleepy mid-market firms to raise their game.

At the time of the deal the two sides talked confidently of the opportunities to cross-sell Pinsents' corporate capability to Masons' construction client base. It certainly seemed to make sense.

The passage of time, however, has dampened expectations, with partners admitting that progress in this vital area has been 'slower than expected'.

So what does the firm have to show for its efforts? The management points to an instruction it landed last summer for legacy Masons client Lend Lease, which it advised on a £245m buy-out of property developer The Crosby Group.

Another Masons construction client, Alfred McAlpine, has also been using the merged firm for corporate and commercial work. But there are precious few other examples of such cross-selling taking place.

According to senior partner Chris Mullen this is not a problem. He says the firm has had more success in cross-selling its pensions, employment and competition capability to Masons' client base. And he backs up this assertion with concrete examples.

He argues that however loyal they are, legacy Masons clients will be reluctant to drop their primary corporate advisers without first road-testing Pinsent Masons' ability to handle general commercial work.

Some rivals will seize on this admission as evidence of the firm's lack of ambition. At the very least, it suggests that the expected benefits of the merger are taking longer than expected to fully materialise.

And in such a competitive market, time is not on its side. Already, in the short period since the merger, the firm has lost three heavyweight corporate partners.

Last September the Birmingham office was hit by the departure of head of corporate Gary Laitner and head of infrastructure and construction Paul Finlan to the London office of US firm Crowell & Moring.

In Manchester, rated corporate partner Mike McGrath will soon be leaving for an in-house role at Speedy Hire.

The firm is expecting to improve on last year's average profits per equity partner figure of £234,000. This will help to convince its partners not to lose faith in the merger. Then again, Pinsents is by no means the only firm expecting a substantial boost in profits this year.

And it has a long way to go before its merger is viewed in the same light as the one between national rival Addleshaw Booth & Co and Theodore Goddard in 2003.

After all, at £404,000, Addleshaws' average profits per partner are almost twice those of Pinsents.

This speaks volumes about the uphill task that lies ahead of Pinsents if it is to rid itself of that 'sleepy' label.