British travellers will have to pay €7 for a three year pre-travel authorisation to visit the European Union after Brexit, provided London seals a divorce agreement with the EU.

The EU is readying a new electronic visa waiver system by 2021 to beef up security.

Its executive proposed to exempt Britain from visas provided that the sides agree on a Brexit deal before the UK leaves, as is now due on 29 March 2019.

The new EU system, or ETIAS, would be similar to the ESTA scheme used by the United States, and would apply to countries outside the EU whose citizens can travel to Europe visa-free.

There are currently 61 such countries from Monaco to Australia.

ETIAS would start applying to the UK after its status-quo transition after Brexit runs its course, which is now due at the end of 2020, though it could be extended.

The fee would be waived for travellers under 18 and those over 70 years old.

Read More: 

Taoiseach 'very satisfied' with EU position on backstop
Brexit bother: May remonstrates with Juncker 
More Brexit stories

It would also cover countries associated with the EU's zone of control-free travel, meaning Britons would also have to pay to travel to Norway, Iceland, Switzerland and Lichtenstein since they are part of this so-called Schengen zone even though outside of the EU.

Conversely, it would not cover EU states that are not in Schengen, such as Ireland.

If Britain crashes out of the EU with no agreement in place to mitigate ensuing disruptions, Britons could require visas to travel to the EU in the future, a spokeswoman for the European Commission said.