Agents often get a bad reputation. During property booms, there have been cases of real estate agents telling buyers a house is on the market when it isn't so they can make an approach to the owner with a potential offer. Sports agents are sometimes accused of suggesting a club might be interested in signing a player, just to see if the player is keen.

But few would have thought that similar tactics would ever enter the legal recruitment market in a major way.

And yet it seems they have. The hiring market for private equity partners in London is so hot at the moment that lawyers are complaining of similar behavior.

Some private equity partners complain about being marketed by recruiters without their permission. One says he received a call from a friend at a rival firm asking if it was true that he was on the market. The partner in question had just been marketed by a recruitment agent with whom he had not even spoken.

Partners add that they are also being approached about joining firms that recruiters haven't been mandated by.

One law firm head says he sometimes gets approached about specific partners with whom a recruiter may or may not have spoken. He has to explain to the recruiter that he is happy for them to signal that the firm may be interested in the partner, but that they must make it very clear they are not being mandated by the firm and they must not approach other partners. "It's like talking to children," he says, adding that they typically still do approach others.

The incentive for agents to operate in this way is clear. Recruiters typically stand to receive a fee that is 25% of the annual remuneration of a person they place. For highly sought-after individuals, this can be quite profitable for the agents involved, so it is perhaps understandable that they would do whatever they can to get in ahead of their rivals.

The tactics are not all that new and by no means confined to just private equity, but the surge in private equity work and subsequent hiring war has magnified the effect in that sector and attracted attention.

Partners are understandably frustrated, as are those responsible for hiring. No one wants to appear like they're making multiple approaches, lest they appear slightly desperate.

Some recruiters also feel resentful of their counterparts' actions because they risk being tarred with the same brush.

"We are aware that this happens, and it is very bad for the industry because when we call them up there is always something to overcome," says Scott Gibson, a recruiter at Edwards Gibson.

And yet, while one recruiter called the behavior "disgraceful," there also seems to be a grudging acceptance that this is simply a function of a manic hiring market. In the last few months alone, private equity hires have been made in Europe by the likes of Kirkland & Ellis; Clifford Chance; Simmons & Simmons; Weil, Gotshal & Manges; Akin Gump Strauss Hauer & Feld; Vedder Price; and Willkie Farr & Gallagher.

This is not a practice area in which firms want to be only a little bit larger. Private equity has come to dominate corporate transactions in a way no one expected a decade ago. Not only do buyout firms offer a steady stream of M&A mandates, they also provide opportunities for restructuring, finance, tax and property departments. Any partner with links to such influential clients will be highly sought after.

One private equity partner says demand is so strong you would have to be "comatose" for a firm not to be interested in hiring you at the moment.

Good news for the agents maybe, but such dirty tricks are certainly not a welcome market development.