Having freelanced in London, I can say, if anything, the author is understating just how bad agents are there.

Everything is rosy when times are good. When work is plentiful and qualified workers are in short supply agents are your friends. But having lived through the IT recession in the early 2000s in the UK, I can tell you that there's a whole other side to that coin.

In 2003 the unemployment rate amongst self-identified contractors was 39%. THIRTY NINE PERCENT. And that didn't include those that had left the industry, taken permanent jobs or retrained (many as plumbers for some reason).

In this environment the agents are the worst enemies of both the contractors and the companies.

Some things worth knowing:

- When a job is officially posted, many companies will have PSLs (preferred supplier lists). These are 5 or so agents who they will source all their contractors from. For this reason alone you need to spread yourself around a few. Deutsche Bank's set of 5 might be completely different to, say, CSFB;

- Often the PSLs will be able to submit a quota of CVs, often 2. 2 x 5 = 10 CVs to review. This has some unfortunate side effects, namely you have no idea if you've actually been submitted for a job or not. Let me explain:

- When you respond to an ad, the agent will typically filter you through some basic questions (of which he or she typically has no clue regarding the correctness of your answers but, hey, if you sound confident you must be right). After that they will say they will submit you. They may even be telling the truth at that point. Or they might be lying. If they say they won't put you forward you'll go through someone else and how embarrassing would that be if they turned you down and you got the job through someone else? Better to sideline you in favour of a candidate that looks better on paper;

- Even if they intend to put you up, a better candidate may come in before the submission deadline. Will they tell you they're no longer submitting you? Not at all. They'll simply quiet drop you, effectively sidelining you;

- If companies get the same CV from multiple sources that will often kill your application as the company doesn't want the fight with the various agents as to who is entitled to the commission;

- Before a hiring manager or line manager even sees your CV it has to make it through HR (in large companies). HR has no idea what your technical CV means. They simply scan it for known keywords and acronyms. The result? You have to fill your CV with acronyms to pass this filter.

Example: I once told an agent I had 5 years of Java experience. He said (literally) "that's great but do you have any J2SE experience?" I'M NOT MAKING THIS UP.

- When times are lean (and even when they're not) recruiters will proactively recruit for managers they know. To do this they will tell the prospective candidate the position is live. 90% of the time this is a waste of your time.

Many (but not all) companies use job reference numbers for live positions. You need to learn which companies do and which don't. You can ask for this. If the agent is cagey about giving this information or they say the company doesn't use this when you know they do, just hang up. They're wasting your time.

But some positions are basically filled before they officially become live. Line managers need to wait for approval for hires, budget and so on. Like anything, once it's all official they need someone yesterday. Some will try to expedite the process before filling the position before it's official so you need to walk a tightrope here between wasting your time and missing out on good opportunities. This will come down to your relationship with the agent but it is so hard to figure out if someone is full of it or not;

- Agents set up fake interviews to make it look like they're getting things done for you. They day before (or even the same day) they'll cancel the interview saying something has come up. Do yourself a favour: if this happens, ring the company and speak to the person involved. This may be hard to do as agents are there to shield them from direct contact but persevere. Some will care but many won't. At least you can figure out if the agent is full of it or not;

- Agents advertise fake positions to harvest CVs;

- Agents will submit you without your permission. I've had my CV turn up for the same job from 5 different agents (literally). That killed the position for me through no fault of my own;

- Agents will want CVs in Word format. This is partly for convenience but also they will often change things. You could mitigate this by sending a protected PDF CV for each position. Some will drop you if you create this hassle for them but if you want to control who sends out your CV, it may be worthwhile;

- You have no control of the markup the agent will charge on top of what they pay you. Combined with a lack of technical expertise, the agent may hurt you in this regard without you being able to do anything about it.

Let's say your market rate is 400 pounds/day. If that's too close to the maximum the agent might not put you up even though you're the best candidate. They simply won't make the margin they want.

Or you can go in with a low quote because you're not entirely suited to the job or its a company you really want to work for. The agent may mark you way up anyway, putting you out of the running. They can do this simply because they don't know your deficiencies for that application.

Honestly I could go on. Contracting in London for me was an horrific, anarchic, soul-destroying experience. Recruitment is one of those industries in the UK in drastic need of regulation to stop these shenanigans.