"Every year, people drown in the sea and in swimming pools in Portugal. Take care when walking close to the water’s edge, especially along unsupervised stretches of beaches. Waves can be unpredictable and have a strong undertow.

"Do not swim at beaches that connect to or from rivers as they can have strong undercurrents, swim at any beach without lifeguards, and dive into unknown water as hidden rocks or shallow depths can cause serious injury or death.

"Beware of rip tides, which can cause drowning. If you are caught in a rip tide, do not try to swim against it. Swim parallel to the coastline until you no longer feel the current, then try to swim towards the shore.

"Follow any lifeguard instructions and warning flags. Red means danger: do not go into the water, yellow means caution: you can walk in the water, but you cannot swim, and green means it is safe to swim in the water."

The Foreign Office added: "Look out for signs warning of cliff erosion. Falling rocks are a hazard, particularly in the Algarve”.