Holidaymakers in Spain could be left "homeless" by a new rule change that comes in to force today. The beginning of July coincides with the implementation of a mandatory national registry for short-term rentals.

This includes tourist accommodations like those found on Booking.com and Airbnb - online platforms that are popular with British tourists. Tourism industry insiders, however, fear that the new rules could exclude 70% of the current supply, potentially leaving visitors without a place to stay.

Silvia Blasco - the president of the Spanish Federation of Tourist Housing and Apartment Associations (Fevitur) - warned that flaws in the new registry system could leave many without a roof over their heads.

She explained: "Families who have booked an apartment or holiday home are likely to be left without accommodation.

"This is because a large part of the legal supply cannot be registered in the Single Digital Window system and will disappear from the platforms."

Blasco argued that current registry systems operated by local communities were more than adequate to deal with the situation.

She said that the new rules were perceived as "a centralising instrument that duplicates existing structures and adds unnecessary complexity to the system".

Moreover Fevitur's president attacked "the arbitrariness and lack of uniformity" of the application process, which was leading to some accommodations being unfairly denied registration.

Tourists have been urged to check their accommodation is compliant with the new rules.

People should look for a registration number that ought to be clearly displayed on the property's listing.

If the number is missing, people should contact their host and request it before confirming their booking.

Visitors should also ensure that their online booking platform has taken the necessary steps to verify listings.

Fevitur believe the new system could potentially cost the Spanish economy an eye-watering €13.7 billion over six months from July to December, as well as a rise in illegal housing.

The introduction of registration codes for short-term rentals is a long-term strategy to manage tourism and create a more sustainable and responsible travel environment.