WITH half-term over, thoughts turn to booking a week off at Easter or two weeks in August. And, like it or not, you should think about travel insurance. If you don’t take it out when you buy your holiday, you could find yourself without cover if you have to cancel.

The first rule of thumb is, never buy from the travel agent or tour operator. More than half of tourists still do, even though it could cost twice as much.

Thomson, the package holiday firm, charges £98 to cover a family of four travelling to Greece for up to 17 days, whereas one of the cheapest policies on the market would set you back only about £30 - and the cover might well be better.

Consumer groups today called for insurance sold by agents to be regulated following a damning report from the Treasury select committee.

It can be difficult to resist the hard sell, though. A survey by Direct Line found that one in five people had been told by an agent they could not travel without taking out their policy.

The second rule of thumb is that an annual multi-trip policy will generally be cheaper if you are abroad for more than three weeks a year. Boots charges £40 for a single-trip policy for a family of four, but the same family could get cover for the whole year for only £89.

Always check if you are doubling up on cover. For example, your home insurance may already cover you for the theft or damage of personal belongings on holiday, so you could waive this element.

And always tell your insurer if one of your relatives is ill. If you have to cancel your holiday and you have not mentioned it, insurers are within their rights to turn you down.

If you disclose the information, there is a chance the insurer will refuse cover or charge a higher premium — but at least you can seek an alternative. Some also turn down claims because of their definition of a relative. Godparents may be excluded, for example.

Websites such as insuresupermarket.com will help you find the least expensive policies, but the cheapest is not always the best value.

You should always check the level of cover on offer. Defaqto recommends medical expenses of £1m in Europe and £2m in America; liability of £2m, cancellation of £3,000, legal expenses of £50,000 and baggage cover of £1,500. This should cover most problems.

So here is my pick of the three best travel insurers.

1 Direct Travel

THIS firm is a good bet for a family of four wanting an annual multi-trip policy that includes winter sports. Its Premier policy covers anywhere in the world for all trips, as long as they are no more than 45 days at a time, for only £99.

The policy, underwritten by insurance giant Axa, will cover medical expenses of £10m, personal liability of £2m and personal possessions of £1,500 with a single limit of £250 and £4,000 for cancellation.

If you want the winter-sports cover, you will also get £15 a day if the piste is closed, up to a maximum of £300.

Closure is defined as 80% of ski lifts and ski schools being shut. You will also get £400 if your ski equipment is lost, stolen or damaged.

2 Boots

THE high-street chemist has an insurance arm and scores well on single-trip policies for a family of four.

If you want to limit the cover to Europe, you would pay £40, or £79 if you are going further afield. You get cover of £10m for medical expenses, £3m for personal liability and £5,000 for cancellation.

3 M&S

MARKS & SPENCER may be better known for its underwear ads at the moment, but its travel insurance is a good deal, especially if you are over 65.

Older holidaymakers often struggle to find competitive travel cover, but M&S has no maximum age limit and would charge £69.89 for a couple both aged 69 travelling in Europe for up to 14 days, and £147.51 including the US.