Generally you need to have sorted travel insurance before you depart, but like all insurance there will be someone who will cover him, it’s just a question of cost!
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As a citizen, you can buy a policy even if you’re already travelling, working, living or studying in another country.
If you buy a policy away from home, there is a waiting period of 3 days before the insurance takes effect. In the event of serious injury in connection with an accident, you will be covered from the date cover commenced subject to the accident being witnessed and verified by an independent third party.