Can there be any issues with a temporary passport when travelling to UK as EU citizen as there is no biometric chip included?
The German government site claims that it's possible (Vorläufiger Reisepass: Ja).
But I've found no such statement on the UK government site.
TravelDoc says (for travel from Germany to the UK with a temporary passport):
Visa is not required for passengers who either hold an Emergency Passport, Temporary Passport, or an Emergency Travel Document (ETD) issued by a European Economic Area (EEA) country or Switzerland. These documents are accepted in lieu of an ordinary passport.
The IATA Travel Centre also says it's fine even when told the document is a temporary passport and is not biometric but is just machine readable.
Obviously you won't be able to use the e-Gates.
