Half-term holidaymakers heading to Spain's Costa Blanca could be confined to the swimming pool if they fancy a dip.

That is because an invasion of Portuguese Man O' Wars has closed most of the region's beaches to swimmers.

At the weekend, an 11-year-old boy was taken to hospital after suffering a sting from a Man O' War at La Marina beach near Elche on the Costa Blanca.

The jellyfish-type creatures carry a potentially deadly sting in their tentacles, which can grow up to 50 metres.

A Portuguese Man O' War that has been washed on to a beach

Around 75 miles of coastline has now been closed to the public. Nearly every beach from El Campello - which is north of Alicante - down to Pillar de La Horadada - which is south of Murcia - is currently off limits.

Only two beaches on that stretch of coastline are still open to holidaymakers. As it stands there have been no Man O' War sightings at either San Juan or El Postigue - both of which are just north of Alicante and remain open.

But there have been sightings of the deadly creatures as far south as Orihuela Costa.

Orihuela Town Hall tweeted: “We ask you to be careful because of the presence of Portuguese Men O’War on our coastline. They shouldn’t be touched.

“Two of these creatures have so far appeared in the water at La Caleta beach. The public should be extremely careful because their sting can be very dangerous.”

The area of Spanish coastline affected by an invasion of Portuguese Man O' Wars

Portuguese Man O' War are usually confined to the Atlantic but they are transported by currents and sometimes find their way into the Mediterranean. This particular invasion has been blamed on a strong westerly winds.

What to do if you are stung by a Portuguese Man O' War

Always seek help from a lifeguard first but if one is not available follow this advice:

Do:

  • rinse the affected area with seawater (not fresh water)
  • remove any spines from the skin using tweezers or the edge of a bank card
  • soak the area in very warm water (as hot as can be tolerated) for at least 30 minutes – use hot flannels or towels if you can't soak it
  • take painkillers like paracetamol or ibuprofen

Do not:

  • use vinegar
  • pee on the sting
  • apply ice or a cold pack
  • touch any spines with your bare hands
  • cover or close the wound