Travel insurers will come under fire in a new report to be published by the Financial Services Ombudsman (FSO) this week.

Complaints about the mis-selling of travel insurance have soared in recent years and now account for one in eight of all disputes between consumers and insurers.

Financial Services Ombudsman Walter Merricks accused travel insurers of providing a “haphazard” service. He will warn insurers that they must fully explain policy exclusions and not rely on the customer to scour the small print.

He said: “Travel insurance is perhaps the most complex financial product consumers purchase during the year. We do not agree that customers should be expected to familiarise themselves with unusually complicated provisions.”

Supermarkets, internet insurers, travel agents, banks and building societies will come under the spotlight for failing to explain the basics of cover.

Many travellers are unaware their policies do not provide adequate protection for hazardous sports, such as sky diving or hiring a motorbike, or pre-existing medical conditions such as diabetes.