Originally Posted by lilpilot
BASA will likely not apply to UK license holders as the UK leaves the EU and BASA is an EU-US agreement.
That is an irrelevant fact. EU residence is not required to hold a Part-FCL licence and, in the context of this thread, conversion to a Part-FCL licence under the BASA is unnecessary.
If the OP obtains a Part-FCL licence it will be deemed valid for use in UK and there is no indication that article 150 of the UK ANO will be changed once UK leaves EU.
In the worst case UK will withdraw from the recent agreement (number
5950) registered with ICAO on the
automatic validation of Part-FCL licences: see also
Commission Regulation (EU) 2018/1065 of 27 Jul 2018 amending the Aircrew Regulation, and
amendment 174 to ICAO Annex 1. As far as I can see this will only affect holders of UK-granted Part-FCL licences operating non-UK-registered EASA aircraft outside UK and EU. The obvious solution is to apply under ANO Art 152 (form SRG 1104) for a United Kingdom pilot's licence, which post-Brexit will be valid on UK-registered aircraft presently considered EASA aircraft, then change the Part-FCL licence State of Issue.