Subject to compliance with the revalidation/renewal requirements your licence and ratings will remain valid for non-EASA aircraft only into the future. If you intend to fly EASA aircraft after the EU rules are fully implemented you must obtain an EASA licence. The European regulations allow a transition period for this. A UK ATPL or CPL may be used to fly EASA aircraft that are within the scope of the licence and the valid ratings in the licence until 7th April 2014. The transition arrangements for the introduction of the LAPL mean that a UK licence may continue to be used until 7th April 2015 to fly EASA aircraft under 2,000 kg MTOM and with not more than 4 occupants, in VMC, for private purposes only.
To continue to fly EASA aircraft after the relevant end date, the holder of a UK ATPL / CPL must apply to the CAA for a Part-FCL licence, with evidence that he complies with the conversion requirements set out in Annex II of the “Aircrew” licensing regulation. See also CAP 804. Assuming that compliance is shown, the licence holder will receive a non-expiring EASA Part-FCL licence with the Part-FCL ratings that are valid on the date of issue. With the 2012 amendment of the Air Navigation Order the ratings contained in a Part-FCL licence will be valid for the piloting of non-EASA aircraft within those ratings. If the UK licence contains UK-specific ratings, such as a microlight rating, the licence holder may also be granted a non-expiring UK licence containing those ratings. If the UK licence has expired, the requirements for re-issue must be complied with before the Part-FCL licence is issued.