It's not a US/UK cultural difference nearly so much as it's a public/private sector one. The informal job market is just as big here, and a huge thing we promote to students, although as someone who has always worked in the public sector, it terrifies me! But yes, we absolutely promote networking and speculative enquiries and dropping off CVs and introducting yourself to employers, and a huge percentage of UK jobs are found that way. Corporate graduate recruitment tends to work like the public sector in that it's very structured, but beyond that, it's very much about informal recruitment.

One of the graduates that came on our course last year got a job from spending a few days in London, calling into offices of all the interior design companies she could find, and dropping off her CV and trying to get a few minutes conversation with either the head of the agency or the head of recruitment.

It starts to work once you have specialised a bit, when you can sell yourself not just as "talented person looking for job" but "hi, I'm here, this is what I can do for you - are you interested?" I found it impossible straight after my PhD, but now I'm getting a bit more specialised and experienced in my area, it makes a lot more sense.