Buying a policy.
Buying cover from your travel agent is the easiest way to get travel insurance but probably not the best. Some travel companies offer 'free' cover but it's unlikely that the insurance really is free, as the cost is generally built into the price of the holiday. Remember that commission on selling insurance is a huge earner for travel agents. You can usually get a better deal via an insurance broker or an insurer that sells its products direct to consumers. Try Boots, Churchill, Club Direct, Columbus, Direct Line and World Cover. They often charge half as much as the travel companies.
Travel agents cannot advertise big discounts on holiday prices and then say they are only available to people who take out their 'own label' travel cover. But they are within their rights to make it a condition of booking that you have some form of insurance in place, so it makes sense to have your policy details with you when you book - some agents will demand to see a policy document. Unscrupulous agents may try to say the insurance you do have is not good enough in a bid to persuade you to pay for their own cover. This is technically legal, but goes against the spirit of the rules guiding insurance sales. So resist their pressure and stick to your existing policy - or go to a different agent.