Section 18 of the Enterprise Act 2002 applies to any claim for damages, or any other claim for a sum of money, which a person who has suffered loss or damage as a result of the infringement of a relevant prohibition may make in civil proceedings brought in any part of the United Kingdom. See also OFT's guide to private litigation in competition cases: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/520423/competition-law-redress-a-guide-to-taking-action-cma55.pdf