Millions of Brits have been warned to renew their passports by tomorrow or they could face being banned from entering the EU in a No Deal Brexit scenario.

With three weeks to go until Brexit on March 29, consumer group Which? has warned travellers who have less than 15 months left on their passport to apply for a new one now if they plan to travel after we leave the EU.

Earlier this year, the government issued advice that EU countries could bar Brits from entering if there is a No Deal Brexit.

The UK Foreign Office warned: "If the UK leaves the European Union with no deal, the passport validity rules for travel to most countries in Europe will change from 29 March 2019.

"Some passports with up to 15 months validity remaining may not be valid for travel."

This is because when passports are renewed, up to nine months of validity from the old passports are carried over.

However, in a No Deal situation, the time carried over will no longer be valid.

Countries popular with British tourists like France, Spain and Portugal could all be affected.

This could lead to a rush in passport applications in the UK following previous advice that just six months validity would be needed.

Passport renewal can take up to three weeks to arrive, although it can be much longer during busy periods

Britons travelling immediately after Brexit in March, for example, would need to have a passport which is valid until at least June 2020.

According to Which? Travel's figures obtained from the Home Office, approximately 3.5million British passports won't be valid in a No Deal situation - with 1.5million of those set to travel in the spring or summer.

Additional driving permits after Brexit may also be needed, according to the Foreign and Commonwealth Office in the event of a no-deal.

There are three types of International Driving Permits (IDP) which may be required, depending on the country.