ACAS
ACAS is an acronym for the Advisory, Conciliation and Arbitration Service. It is a government funded independent body offering conciliation services to parties involved in employment tribunal claims. ACAS also provides Codes of Practice, advice and guidance on workplace issues to individuals and employers.
See
Acas code of practice 1 on discipline and grievance procedures
without prejudice communications and discussions
without prejudice subject to costs offers
How to complete the employment tribunal claim form (ET1)