An Assessment Centre is a place where employers bring together candidates who have applied for a particular role. Candidates are put through a series of tests, assessments and group/individual exercises to determine their suitability for the role and comprehensively assess their abilities.
An Assessment Centre may include social/informal networking events, interviews, report-writing, group discussions, data analysis and delivery of presentations.
For general advice on preparing for all kinds of Assessment Centre activities and exercises, check out gradireland's Assessment Centres page.
Target Jobs have an in-depth guide to specific types of Assessment Centre activities and some great advice on how to approach these activities, successfully demonstrating both your teamwork and leadership skills.
Prospects also provide some useful tips for doing well on the day and give an example of a typical Assessment Centre schedule.
If you have an Assessment Centre coming up that involves psychometric tests (for example verbal, numerical or abstract reasoning assessments) you can get some practise with Profiling for Success.