A member state fails to meet the convergence criteria for participation in stage 3 Derogation can be lifted if the member state subsequently meets the criteria
(law) the partial taking away of the effectiveness of a law; a partial repeal or abolition of a law; "any derogation of the common law is to be strictly construed"
Individual states may enter into a derogation (opting out) in respect of certain Articles during times of war or other national emergency The UK government has entered into a derogation in respect of Northern Ireland, which has the effect of limiting the effect of certain Rights under the Convention