Millions of Britons travelling to troubled Spain will not be covered by travel insurance if they are hurt in a terrorist attack.

Last week, 13 tourists were injured in a huge car bomb blast in the popular northeastern resort of Salou, near Tarragona.

It was the latest in a series of attacks by Basque separatists ETA, who have been targeting Spanish tourist resorts since March.

Insurers typically refuse to reimburse customers for cancellation of the holiday under these circumstances, unless the country has been declared a no-go area by the British Foreign Office.

But some also refuse to offer medical expenses for those caught up in any terrorist event or war.

A spokesman for travel insurer Club Direct said the company would not cover medical claims for customers injured as a result of the troubles in Spain, unless they bought their insurance before the bombing campaign started.

Columbus Direct admitted it had the same policy. A spokesman said: “We are warning people that there is limited cover.”

Millions of holidaymakers could be subject to the policy exclusions – more than 12 million holidays are taken by Britons in Spain each year, making up 40% of the country's holiday market.

Royal & Sunalliance (R&SA) travel insurance manager Fiona McDonald said the company was one of the few insurers that would offer full medical cover for people travelling to Spain.

“If we refuse to accept cancellation claims, it would not be appropriate to say that if you get caught up in a bombing, we will not cover you,” she said.

The Foreign Office is not advising travellers to avoid Spain, but has warned if there was another attack in a tourist area in Spain, the chance of a tourist being hurt would be “relatively high”.

Last week, the Financial Services Ombudsman (FSO) accused travel insurers of providing a “haphazard” service.

It told insurers they should fully explain policy exclusions and not rely on the customer to scour the small print.

The FSO report revealed complaints about the mis-selling of travel insurance had soared in recent years and now account for one in eight of all disputes between consumers and insurers.