The ACAS Code of Practice became effective from 6 April 2009. Employment Tribunals must take into account the parties compliance with the Code and if they have unreasonably failed to follow one of the Code's provisions, the Tribunal:

• can take into account the party's failure in deciding the merits of the case; and
• may increase or decrease compensation by up to 25% in the case of claimants 
  

One main difference of the Code to the previous statutory Dispute Resolution Regulations is that non-compliance with the statutory minimum disciplinary and grievance procedures does not automatically result in unfair dismissal.