For an ordinary short visit on a Turkish passport, the starting point is the Standard Visitor visa requirement. An ETA is not an alternative that visa nationals can select because its application appears simpler. Nevertheless, eligibility lists and exceptions can change, so check the GOV.UK visa checker and official ETA guidance before travel. Another nationality may produce a different result when using that other passport, without changing the Turkish passport’s eligibility. Existing UK permission may also matter. Residence in Türkiye, a Schengen visa or a European residence card does not independently establish ETA eligibility.