There are a large number of job boards available for those out of work in the UK. Before I get into a list of those you should use, I want to discuss how to use them for maximum opportunity.
The Right Fit
First, you need to choose the one that is right for you. If you are an executive, you won’t want to use a job board geared toward entry- and mid-level workers. Similarly, if you are a scientist, you aren’t likely to find jobs in your field on a job board that caters to office workers.
Maximise the Features
Many job boards allow you to sign up, create a profile and receive job alerts for newly opened positions in your field. This is a huge timesaver and you should take advantage of it. You will also be able to filter your searches by region or distance from your home. It may help to make a list of absolute requirements (distance, say) prior to filling out your search requirements.
Job boards often allow you to submit your application or CV directly from their site. Upload the most used versions of your CV to make the process more seamless. You may also be able to save cover letters to your account. While having a standard cover letter will make things go quicker, remember to tailor each letter to the specific employer in question.
Now that you have the basics of using job boards, I’d like to provide you with a list of job boards available to those in the UK, in no particular order:
http://www.4jobsonline.com/ (more mid-level/technical)
http://www.eurojobs.com/ (All EU)
Hopefully, this list will get you started. As always, use multiple resources for a serious job search: job boards, a recruiter and personal contacts.