The subject of visas is ever-changing. Not only are the rules and regulations frequently revised, but the way embassies and high commissions impart information to the public and process visa applications is also constantly being altered - and frequently not to the benefit of the traveller. Today there is a steady drift of people trying to leave their country and rebuild their lives elsewhere, safe from war, famine or persecution. This puts an increasing strain on the immigration policies of various governments, and the regulations dictating whether you may enter any given country visa-free are constantly under review. While the situation for UK passport holders is reasonably static, members of other nationalities resident in the UK may be subject to different sets of rules.

The ever-increasing desire to travel and the spontaneity with which travel can be organised has had little impact on the authorities responsible for issuing passports and visas. Some countries have closed their provincial consulates in the UK, thus putting additional strain on their hard pressed London-based staff and guaranteeing long queues, especially at peak travel times. Spain, by contrast, insists that you apply to the consulate closest to your place of residence. It all adds up to the fact that while you can virtually arrange a round-the- world itinerary in a matter of minutes, if your documents are not in order you cannot travel. So some thought has to be given to the matter of your passport and the possible need to obtain visas for the countries you wish to visit.

Efficiency and bureaucracy

The cost to a government of maintaining an embassy or high commission overseas is enormous, and most if not all are conscious of the need to reduce costs or raise extra revenue. Some have introduced premium-rate telephone lines for public enquiries; others have installed automated switchboards, which is fine if you know the extension number you want. You may have to listen to a long message before reaching the information you want, and sometimes your question may not be answered at all. But these methods enable the embassy or high commission to reduce its staff (or with luck redeploy them to issuing visas) and raise revenue from premium-rate telephone lines.

You need to do your research regarding visas early in your travel planning process, for - according to where you are going, your reasons for visiting a country and your nationality - the issuing time can vary from a matter of hours to weeks. It is important to understand the role of the embassy or high commission and its staff. The decision as to whether or not a visa is granted lies in their hands, and any consular official has the authority to reject an application if he or she thinks fit. If a rejection takes place, it may only require an extra supporting document such as a bank statement to resolve the matter. Beware though: the US and India endorse the passport when an application is rejected, whereupon a fresh application needs to be submitted, the paperwork for which has to persuade the embassy to reverse its previous decision.

Understanding

When you set foot in an embassy you are entering the territory of another country; frustrated though you may be after hours of queuing, it is worth remembering to be polite and tolerant with the consular official who deals with you, and who is after all only carrying out the checks and procedures imposed by his government. It may help to remind yourself that British and US embassies abroad can be equally daunting to other nationals. Opening hours are limited in order to enable staff to issue visas once the public have left the premises, but this obviously poses problems for people living a long way out of London. Postal applications are treated as non-urgent, and your envelope may remain in the mail bag for some weeks before it is opened and dealt with by the embassy or high commission. It is unrealistic to expect them to spend time searching for your application among hundreds of others.

It also pays to inform yourself of public holidays, as these authorities close not only on UK public holidays but also on their own. This obviously disrupts the issuing process and causes a logjam on reopening. During the Muslim holy month of Ramadan, embassies of Islamic countries change their hours of business, before closing altogether at the end of it. Be aware also of dates for the Chinese New Year and other important religious festivals.

Your passport

Before you leave Britain you require a ten-year passport. The MRP (machine readable passport) is available in two versions, one costing £28 and the other with additional pages costing £38 at the time of writing (applications made in person or through an agency will be charged an additional £12). Many countries require a minimum of six months' validity remaining on the passport when you either enter or leave their territory, so first of all check your passport's date of expiry. Make sure the passport has a blank page for each visa required, and sufficient space for entry and exit stamps. Some embassies will only issue a visa on a right-hand page.

Ensure your passport is signed. Again many authorities, the Indian High Commission among them, will not grant a visa on an unsigned passport. Some embassies will grant visas with a validity exceeding that of the passport, but others restrict the visa validity to coincide with the passport expiry date.

Take great care of your passport not only when you are travelling but also between journeys. Keep it secure, as a UK or US passport can command many hundreds of pounds on the black market.

Visa requirements

There are many factors to consider here. Business or tourism? How many entries and for how long? The US has over 20 different categories of visas reflecting different reasons for travel - but only one application form. Saudi Arabia has four different forms covering various reasons for travel. Non-UK-passport holders may find their application referred, with a delay of about four weeks, if they are not permanently resident in the UK.

Most visas are valid from the date of issue, frequently for three months. Some, such as those for Russia, are valid from the date you enter the country: in this case the entry and exit dates are clearly stated on the visa and you cannot enter Russia before or leave after the given date. You therefore need to plan when to apply for a visa in order to avoid a situation where it expires before you even arrive in the country. Other countries issue visas which may be valid for twelve months and allow multiple entries with no restrictions.

You will also need to make financial provision for buying visas. The majority cost under £25, and some are free, but others cost considerably more, particularly for business travellers. The price may also vary according to your nationality, as the costs are agreed between governments. To these costs must be added those incurred in actually getting the paperwork to the embassy: are you going to employ the services of an agent who specialises in visa procurement, or resign yourself to spending a lot of time making trips to embassies and waiting in queues?

Some countries, for example Cambodia, Laos, Mali and Mauritania, have no representation in London. Their nearest embassy is in Paris, which can only add to the cost and complicate the logistics of acquiring a visa.

Many nationals have for some years been able to travel to the US for a maximum of 90 days without a visa, providing they meet the criteria set down on the 'waiver' form. If you have incurred a conviction, however, you must declare this and apply for a visa. The Australian Working Holiday visa for those under 26 years of age is valid for 12 months and is an attractive proposition, allowing a period of holiday to be combined with work in order to finance additional travel.

Beware of an Israeli stamp in your passport should you wish to visit the Arab countries in the Gulf area. Instead, ask the Israeli entry and exit controls to stamp a loose-leaf document. A South African stamp in your passport, by contrast, no longer presents the problem that it used to.

Ready to go?

Before you leave, check your visa for accuracy and ensure it covers you for your plans. Mistakes are frequently made owing to pressure of work in Embassies, and even computer-issued visas are only as accurate as those who input the data. If you are taking family members who are on your passport - husband or wife or children under 16 - ensure that the visa covers them as well, or that a separate one has been issued. Some visa application forms, such as those for India, Australia and Egypt, include space for all those included on the one passport; other countries require one completed form per person. Remember that children who have reached 16 years of age require their own passport.

Visa trends

In recent years we have witnessed the break-up of the USSR; the Iron Curtain has come down; Czechoslovakia has become two separate countries, and Yugoslavia has fragmented. In South America, Argentina and Brazil do not require a visa from UK nationals, but tourists to Venezuela will require a tourist card obtainable from the airline on which they arrive in the country (check this when booking your seat).

Although the CIS (formerly USSR) has become more accessible, the documents required for a visa have changed little: you need either an invitation from the company you are visiting, if travelling on business, or confirmation of your accommodation, if travelling as a tourist. Poland, Hungary, Bulgaria and the Czech and Slovak Republics no longer require a visa from UK passport holders, but Romania does. Those requiring a German visa must show the embassy proof of medical insurance cover: if you are a UK resident and registered under the National Health Service, an E111 from the Post Office is sufficient.

The requirements for entering France and Spain on a non-UK passport are complicated, although visas are issued free of charge if the applicant is married to an EC passport holder, on production of the partner's passport and the marriage certificate (not a photocopy). Australian passport holders no longer require visas for France and Spain, but they do need visas for Portugal.

India is an ever-popular destination and the High Commission offers a tourist visa valid for a six-month stay, starting from the issue date of the visa. The cost of the visa is £19.00, though non- UK residents will be charged £10.00 extra and their visas will take up to ten days to be issued (do not in any case apply by post as you will probably not receive your passport back in time). Taiwan has relaxed visa requirements for periods of up to 14 days, depending on nationality. Still in the Far East, UK nationals can stay in Thailand as tourists for 30 days, providing they are in possession of air tickets with confirmed bookings in and out of the country. A two-month stay is allowed in Indonesia visa-free, provided entry and exit are made through designated air and sea ports. Residing with friends and relatives during the visit is not allowed, and not all nationals are permitted this 60-day stay visa-free. China requires a visa for all visitors, as do Vietnam and Myanmar (Burma), which are now being visited in greater numbers.

Finally, even if you have got all your visas, immigration officials have the power to deny you entry to their country if they so wish, and they are not obliged to state their reasons. The US is perhaps the most formidable in this respect, so it is always sensible to have an onward or return ticket with you, together with proof of sufficient funds to support yourself and additional evidence that you have good reason to return to your country of residence from the US.