BeGambleAware signposts support via free counselling and phone
The NHS has a useful page including support links
Mind, the Mental Health Charity has a comprehensive site which includes information, advice and links to support. As well as links to addiction support it includes in its A-Z directory links to other places of support for issues often confronting addicts, such as debt, anxiety, depression.
The Samaritans offer 24/7 support via telephone and the internet.