Since December 2008 warning notices are fixed to contact orders so that the resident parent (often but not always the mother) is aware that false reasons are not to be given to avoid the non-resident parent having contact. Courts are becoming more robust in enforcing contact orders, custodial sentences have been given but this is very much the last resort.
If both parents have parental responsibility and a residency order is in place the resident parent can take the child on holiday for up to 4 weeks without the consent of the non-resident parent, even so it is wise to get the written consent of the non-resident parent or inform the court. Suggestions have been made that the resident parent who falsely denies access should lose their driving licence and other penalties, but these are for consultation only at this stage.