Ahead of a so-called "summer of discontent", with travel likely to be affected by strike action, Which? assessed 199 insurance policies offered by 71 providers and rated them on the level of protection offered.

Four in 10 policies did not provide cover for cancellations due to strikes, while one policy offered it as an optional extra. Just six in 10 of the policies covered travellers for cancelled trips due to strikes, meaning a significant proportion of travellers could find themselves unprotected.

Which? also assessed covid cover in insurance policies as part of its review, and found huge disparities in the level of insurance, though two thirds of policies offered cover for medical care and cancellations due to covid.

Out of 199 policies, less than 10% offered complete protection including emergency medical care and the option to claim back costs if a holiday has been disrupted by covid whether because of a positive test, local government policies or advisories against travel.

Which?’s money editor, Jenny Ross, said: “With many airlines warning of widespread disruption this summer and covid cases on the rise, travellers should ensure they’ve taken out adequate insurance to cover any losses or unexpected costs they might face.

“Which? analysis of 199 policies shows that levels of cover can vary wildly in important areas like disruption caused by strike action or Covid.

“We advise travellers to always check policies carefully to ensure they offer the cover that will be most appropriate to their trip, and to ensure they have cover in place from the time of booking.”