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.

he 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 only other nation which has achieved anything approaching the British total, Mr Laycock said, is France – which also holds the unfortunate record for having endured the most British invasions. “I realise people may argue with some of my reasons, but it is intended to prompt debate,” he added.

He believes the actual figure may well be higher and is inviting the public to get in touch to provide evidence of other invasions.

In the case of Mongolia, for instance – one of the 22 nations “not invaded”, according to the book – he believes it possible that there could have been a British invasion, but could find no direct proof.

The country was caught up in the turmoil following the Russian Revolution, in which the British and other powers intervened. Mr Laycock found evidence of a British military mission in Russia approximately 50 miles from the Mongolian border, but could not establish whether it got any closer.

The research lists countries based on their current national boundaries and names. Many of the invasions took place when these did not apply.

The research covered the 192 other UN member states as well as the Vatican City and Kosovo, which are not member states, but are recognised by the UK government as independent states.

The earliest invasion launched from these islands was an incursion into Gaul – now France – at the end of the second century. Clodius Albinus led an army, thought to include many Britons, across the Channel in an attempt to seize the imperial throne. The force was defeated in 197 at Lyon.

Mr Laycock added: “One one level, for the British, it is quite amazing and quite humbling, that this is all part of our history, but clearly there are parts of our history that we are less proud of. The book is not intended as any kind of moral judgment on our history or our empire. It is meant as a light-hearted bit of fun.”

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