Employees employed before 6th April 2012 with a minimum 12 months service have the right 'not to be unfairly dismissed'.  From that date new employees require a minimum of two years. Unfair dismissal can arise from termination of employment by an employer, or constructive dismissal when an employee resigns due to the actions of an employer.  Employers must follow ACAS guidelines on dismissal otherwise any compensation may be increased by up to 25 per cent.