The certificate will certify the holder’s Covid status through either vaccination, testing or immunity from a previous Covid infection.

It will exempt them from more stringent Covid restrictions when travelling between member states.

The presidents of the European Parliament, European Council and European Commission signed the concept into law on Monday (14 June).

Millions have already signed up for certificates after the portal went live on 1 June, with 13 member states already issuing applicants their papers.

The scheme will run for 12 months, starting 1 July.

"The aim of the EU Digital Covid Certificate is to facilitate safe and free movement inside the EU during the Covid-19 pandemic," said the union.

"All Europeans have the right to free movement, also without the certificate, but the certificate will facilitate travel, exempting holders from restrictions like quarantine."

Certification will be free of charge; available in all EU languages in both digital and paper formats; and secure, using a digitally-signed QR code.

Additionally, member states will be strongly discouraged from imposing additional travel restrictions on certificate holders unless they are "necessary and proportionate to safeguard public health".

The European Commission has also pledged €100 million in emergency support to member states to help provide affordable tests.