EVERY SCHOOLBOY used to know that at the height of the empire, almost a quarter of the atlas was coloured pink, showing the extent of British rule.

But that oft recited fact dramatically understates the remarkable global reach achieved by this country. A new study has found that at various times the British have invaded almost 90 per cent of the countries around the globe.

The analysis of the histories of the almost 200 countries in the world found only 22 which have never experienced an invasion by the British. Among this select group of nations are far-off destinations such as Guatemala, Tajikistan and the Marshall Islands, as well some slightly closer to home, such as Luxembourg.

The analysis is contained in a new book, All the Countries We've Ever Invaded: And the Few We Never Got Round To. Stuart Laycock, the author, has worked his way around the globe, through each country alphabetically, researching its history to establish whether, at any point, they have experienced an incursion by Britain.

Only a comparatively small proportion of the total in Mr Laycock's list of invaded states actually formed an official part of the empire. The remainder have been included because the British were found to have achieved some sort of military presence in the territory – however transitory – either through force, the threat of force, negotiation or payment.

Incursions by British pirates, privateers or armed explorers have also been included, provided they were operating with the approval of their government.

So, many countries which once formed part of the Spanish empire and seem to have little historical connection with the UK, such as Costa Rica, Ecuador and El Salvador, make the list because of the repeated raids they suffered from state-sanctioned British sailors.

Among some of the perhaps surprising entries on the list are:

* Cuba, where in 1741, a force under Admiral Edward Vernon stormed ashore at Guantánamo Bay. He renamed it Cumberland Bay, before being forced to withdraw in the face of hostile locals and an outbreak of disease among his men. Twenty one years later, Havana and a large part of the island fell to the British after a bloody siege, only to be handed back to the Spanish in 1763, along with another unlikely British possession, the Philippines, in exchange for Florida and Minorca.

*Iceland, invaded in 1940 by the British after the neutral nation refused to enter the war on the Allies side. The invasion force, of 745 marines, met with strong protest from the Iceland government, but no resistance.

* Vietnam, which has experienced repeated incursions by the British since the seventeenth century. The most recent – from 1945 to 1946 – saw the British fight a campaign for control of the country against communists, in a war that has been overshadowed by later conflicts involving first the French and then Americans.

It is thought to be the first time such a list has been compiled.

Mr Laycock, who has previously published books on Roman history, began the unusual quest after being asked by his 11-year-old son, Frederick, how many countries the British had invaded.

After almost two years of research he said he was shocked by the answer. "I was absolutely staggered when I reached the total. I like to think I have a relatively good general knowledge. But there are places where it hadn't occurred to me that these things had ever happened. It shocked me.

"Other countries could write similar books – but they would be much shorter. I don't think anyone could match this, although the Americans had a later start and have been working hard on it in the twentieth century."

The countries never invaded by the British:

• Andorra
• Belarus
• Bolivia
• Burundi
• Central African Republic
• Chad
• Congo, Republic of
• Guatemala
• Ivory Coast
• Kyrgyzstan
• Liechtenstein
• Luxembourg
• Mali
• Marshall Islands
• Monaco
• Mongolia
• Paraguay
• Sao Tome and Principe
• Sweden
• Tajikistan
• Uzbekistan
• Vatican City