Who wants to get rid of a car in Jakarta? Well, if you've just spent 17 weeks driving all the way from London, there's a fair chance that a plane, with a flight time of 17 hours, will seem much the most attractive way to travel back home. Either way, if you do sell a car or camper van, make sure that anybody who could be affected knows what you've done. Whether you think you still own the vehicle is merely the first stage. The important thing is to be certain that the authorities, both where you bought the vehicle and where you sell it, understand the position. What you have to tell them partly depends on where you bought the vehicle and what its status is.

Buying

Traditionally, the favoured market-place for those planning long overland trips, especially Australians and New Zealanders, used to be a car park on the South Bank of the Thames in London. That this has fallen foul of parking regulations is no great loss: many of those sold at the end of a European tour - or two - have already done a huge mileage and, although there may be nothing obviously wrong with the vehicles, vital parts can be almost worn out, landing you with hefty repair bills soon after the purchase. A better option is to look in the UK's trade papers (Loot in London, Exchange and Mart nationally, with any number of regional alternatives) and find an older model that is much less used. Auctions are another possibility if you know your way around an engine.

Outside Europe, regulations surrounding the purchase of vehicles vary. Many travellers wish to buy Enfield motorcycles in India, but to buy new you have to be a resident, so most people use a local to help, fraudulently, with the paperwork. In the best case it takes weeks for the paperwork to come through and, in any event, bending the law while abroad is fraught with risk. In many countries a cash-rich tourist is a magnet for people with shady vehicles to offload: it's the perfect opportunity to get rid of a stolen car with dodgy paperwork. Buying second hand from other travellers is often an easier option: check the noticeboards at travellers' hostels and don't hesitate to check the regulations with the police.

Obviously, tyres, brakes and suspension should be checked wherever you buy. But, if a long trip is planned through countries where spares will be hard to get, it is worthwhile investing in a professional mechanical check of the vehicle. In the UK the AA, among other organisations, offer this service. After all, even if the seller does provide some kind of guarantee, you're going to have difficulty enforcing it in Kurdistan or Mizoram.

Insurance

Before leaving, it is also essential, if you can, to get full details of the vehicle registration rules for any country you could be passing through. Although these are often available from tourist offices or embassies, the AA and RAC have collated most of the information you will need and provide advice for their members. Insurance cover providing for, at the very least, local vehicle recovery is also a good idea. As most countries charge duty on the importation of cars, those who drive in are also expected to take their vehicles out, even if it is involved in an accident or fire. In Italy, for example, it is illegal to dump a car, and computerised records mean you can always be tracked down.

Breakdown insurance can be expensive, but it probably won't be as expensive as the fine or recovery fee you may end up having to pay a foreign government's embassy for leaving them to clear away what was left of your camper van.

The AA and RAC have co-operation deals with their European counterparts, but once you've crossed the Bosphorous, Mediterranean or South Atlantic, you will probably have to turn to a company that offers near-worldwide cover, such as Europ Assistance (Perrymount Road, Haywards Heath, West Sussex, RH16 1DN, tel 01444 444631). When you come to sell at the other end, immediately contact the insurers to cancel the balance of breakdown insurance time remaining, for which you should get a rebate.

Before leaving the UK, you should take two photocopies of all your motoring documents, including those that prove insurance registration, ownership, road tax and, if applicable, MOT; together with your passport. You should take the originals with you, keep one copy in a locked compartment in the vehicle and deposit one copy in your bank or a PO box at home, where it can be checked out if necessary. This should help you to prove ownership if the police in any country or the insurance authorities require it.

The papers will also be useful when it comes to selling the car - as they show that you own it and are therefore entitled to sell.

Selling

The complications surrounding selling a vehicle depend on where you sell it. If you have a carnet de passage you will need to get the carnet discharged by the local customs office, proving that the local taxes have been paid. Otherwise you will forfeit your bond. The easiest way to sell a car with a carnet in the developing world is to allow the carnet to be stamped out of one country and then enter the next without getting stamped in or having its details entered into your passport or your tourist card. Usually there's a form that can be 'bought' (in Africa a laissez-passer or passavant) that will permit this. This won't work at all borders, but once it does, your carnet will be in order and you'll be free to sell the car and fly home (if no other taxes are to be paid, fast). With or without a carnet, it is a good idea to make sure that the transaction is recorded in the presence of a witness who can be easily contacted later if necessary. Motoring journalist Brian Charig recalls the case of the American student who found a garage willing to buy his camper van in India. In this instance the customer asked the manager of the hotel where the student had just paid his bill with an American Express Card (which is traceable) to witness the deal formally. They wanted to be protected in case something went wrong.

Written proof of sale is a safeguard against someone else committing a motoring offence, or even using the car for a serious crime, after you have sold it. You can demonstrate to the local police that it was nothing to do with you. To tell the police when you sell the car is, in any case, the correct thing to do.

When you sell your car you hope to keep, or spend, all the money you have been paid for it, so it is vital to make sure the contract of sale stipulates that the local buyer will meet the cost of all taxes, import duties or other official fees involved. When a foreigner sells a vehicle to a local, that normally constitutes an import, so be certain that the price you agree is net of all customs dues, sales tax, etc. And before you leave home, check (anonymously) with the embassy of the country where you plan to sell as to how the deal will be viewed by officials. If they record the fact that you bring in a car on your passport or entry document then you're probably not in a good place to sell the vehicle: the people checking you out at the airport customs or passport control may well want to know what you have done with it.

There are one or two legal ways to beat import duties, which can be as much as 400 per cent of the value of the vehicle. If you have owned the car for at least a year, plan to own it for another two, and if it is the first you have imported into that country you can normally take it in duty free. If the buyer is remaining in the country, they could leave it in your name for the required two years. Only do this, however, if you know the buyer well enough, either personally or by repute, to ensure that they are trustworthy. Or you can legally sell it in the zone between two borders, although this would mean the buyer would have to have access to free passage of a fairly large sum of money across the borders. Usually such sharp practice sails too close to illegality to be recommended. The sale between borders scam more often means the buyer plans to dump you in no man's land with no re-entry visa and drive past bribed customs officials, leaving you high and dry - a common trick on Mauritania's borders. Selling to another traveller, diplomat or foreign resident who is, for whatever reason, not bound by local laws is usually safer and more straightforward.

Using the money

A further factor that could influence your choice of where to sell is the local currency status and regulations. Many developing nations have a currency that is not internationally exchangeable, and such regulations are often backed by controls on what you can take out, in both local money and foreign exchange. This means that even if you manage to get paid in a hard currency, a last-minute tip-off to the border guards can result, at best, in your hard-won cash being confiscated. At worst, you'll be locked up as well.

Ideally, choose a country with an internationally convertible currency, such as the Singapore dollar, or perhaps the CFA (African franc, underwritten by the Bank of France). That way, if you do take out the payment for the car, you will be able to change it into money you can spend at home.

If you cannot plan to land up in a hard currency nation, find out what the local exchange control rules are. Many countries are so short of hard currency they must restrict its use to buying essential imports, and these are unlikely to include fifth- hand cars from foreign tourists. Even some countries that do have a convertible currency restrict what funds can be taken abroad.

The simplest answer might be to check before you leave what you can buy with the local money - food, souvenirs, hotel accommodation or air tickets - and spend your takings on the spot. But most cars, in the developing world, are worth an awful lot of handicrafts.