Maria Pittordis, a partner at law firm Hill Dickinson, said: “Some companies are getting 100 claims per day. They are all for all-inclusive holidays. Most of them – 99.9% – are from people who did not report their illness in-resort.

“It’s out of control and doesn’t seem to be subsiding, and it’s costing the travel industry quite a lot of money.”

The gastric illness claims started coming in – despite a reported fall in rates of holiday illness – following civil justice reforms in 2012, which have encouraged some law firms and claims management companies to persuade holidaymakers to file such claims against tour operators.

The reforms also mean that travel companies face legal costs that are “disproportionate” to the amount of compensation awarded to customers.

The number of cases surged dramatically in 2016. For example, claims from guests at one Majorcan hotel increased from 7 in 2015 to 350 last year.

Hotels on the island are reported to have paid out £42 million during the first nine months of last year.

Abta, operators, hotels and insurers are all currently lobbying the Ministry of Justice for a change in the rules, to discourage many of these claims.

“They [the claimants] self-medicate, do not go to a GP and a lot of the claims are from holidays nearly three years ago,” said Pittordis. “The claims are just standard letters and sometimes they forget to change the word ‘ship’ to ‘hotel’.

“It’s of particular concern to hotel insurers – some insurers are considering their position on whether to continue to write these policies.”