If the scrap of paper is issued on the back of an effectively expired license I would say the scrap of paper is even more worthless than is usually the case.
Effectively he is flying unlicensed, and could and indeed should be prevented from commanding an aircraft in UK airspace if this lapse comes to the appropriate authorities attention, whether it is the home country of the licence or A.N.OTHER.
Of course "could" and "should" are not the same as "will".
One of the mysteries of this whole story is how the guy managed to get a Turkish (UK too when with Jet2? ) validation without either of these, and possibly other authorities, cross checking with the Swedes that his ATPL and B737 rating actually existed.
For me , that is perhaps even more scandalous than the actions of the individual concerned. Finally, if no one checks, why do they bother giving you a validation anyhow. . . dog licence ? T.V. licence ? fishing permit ? Yeah Yeah any of those will be fine
