The UK Government has provided advice regarding the impact on travel to the EU if there is no deal, from the 29th March 2019

The main issue is one of passport validity.

You will have to show that your passport is still valid for at least 6 months from the date you arrive in the Schengen area.

If you have an adult passport that was issued for longer than 10 years, any extra months beyond 10 years do not count.

Full details are available on the UK Government Website here.

There is also an online calculator to check if your passport has enough time left