World in conflict: Killers seeking sanctuary from hell they made

Of the 104 refused citizenship during 2008 and 2009, the highest number come from Sri Lanka, a country beset by a 30-year civil war with the rebel Tamil Tigers until the government finally crushed the resistance last year.

It was a conflict notorious for its use of child soldiers and the first modern day use of large scale suicide bombing. The Tamil Tigers were branded a terrorist organisation by many countries, including the UK.

What war crimes the 21 Sri Lankans refused citizenship may have committed is not known but up to 100,000 people died in the conflict – tens of thousands of whom were civilians.

Two countries indelibly linked with British military intervention provide the second highest number of suspected war criminals refused UK citizenship – Afghanistan and Iraq.

Afghanistan has endured more than 30 years of conflict, much of it marked by brutal suppression. From the Russian-backed occupation through the civil wars involving the US-backed Mujahideen and then the Taliban, the civilian population has been subjected to the full range of crimes against humanity.

The 13 suspected Afghan war criminals could have been involved in civilian massacres, summary executions, kidnapping, torture and mass rape.

Iraq's bloody modern history provides a similar backdrop for the 13 Iraqis refused citizenship.

From the Iran-Iraq war between 1980 and 1988 through civilian massacres under Saddam Hussein, to the internecine bloodshed after the 2003 invasion, the number of crimes against humanity is incalculable.

The bulk of the remaining suspected war criminals hail from a series of African countries scarred by vicious civil wars.

Twelve come from Angola, which endured nearly 30 years of internal conflict after gaining independence from Portugal in 1975 with an estimated 500,000 lives lost. The conflict involved ethnic cleansing, massacres, summary executions and the use of child soldiers.

Another 11 suspected war criminals come from Ethiopia, which convicted its own former dictator Mengistu Haile Miriam in 2006 of genocide for the mass murder of political opponents before he was ousted in 1991. The civilian population has since endured further massacres and ethnic cleansing.

Neighbouring Eritrea's history has been entwined with Ethiopia with whom it fought a war for independence for 30 years until 1991 and then a new war between 1998 and 2000 which involved systematic ethnic cleansing. Three suspected war criminals refused UK citizenship come from Eritrea.

A further 10 come from Rwanda, possibly the country most associated with modern genocide. Around 800,000 people died in little more than 100 days in 1994, largely the minority Tutsi ethnic group slaughtered by majority Hutus.

The ethnic strife in Rwanda also spilled over into neighbouring Democratic Republic of Congo, where at least three million people died in a civil war, which ended in 2003, and further internal conflicts since. The 10 suspected war criminals from the DR of Congo denied citizenship in the UK could be responsible for civilian massacres, torture, rape and the recruitment of child soldiers among a catalogue of crimes against humanity.

The systematic amputation of limbs was the signature of the decade-long civil war in Sierra Leone, homeland of four suspected war criminals. Widespread rape and sexual abuse was another prominent feature of the conflict in a country which has since formed its own UN-backed war crimes tribunal.

Civilian massacres and summary executions are among the crimes against humanity committed in neighbouring Congo from where two of the suspected war criminals hail.

A 16-year civil war in Burundi, characterised by widespread and systematic murder, summary execution, rape, and torture, spawned significant numbers of war criminals. Among those denied UK citizenship, three suspects are from Burundi.

Closer to the UK, one of the suspected war criminals is from Croatia, which witnessed horrendous ethnic cleansing along with Bosnia and Serbia when the former Yugoslavia collapsed into civil war in the early 1990s.

The last of the 104 suspects is from Iran, where the Revolutionary Guard has been implicated in the killing of thousands of opponents. Last year, Canada deported a former Revolutionary Guard to Iran, on the grounds that the organisation had committed crimes against humanity.

International codes protect humanity

The generic term 'war crimes' actually covers three areas – genocide, crimes against humanity as well as war crimes themselves – acts committed outside the normally accepted rules of war.

Anyone going through the immigration system in the UK can be denied the right to remain if they are believed to have committed any offence covered by the term war crimes – unless they can claim their human rights would be infringed if they were forced to return.

The terms genocide, crimes against humanity and war crimes are defined by a statute of the International Criminal Court.

Genocide involves acts intending to destroy a national, ethnic, racial or religious group primarily through killing people though also through other means such as "imposing measures to prevent births within the group."

Crimes against humanity include a wide range of actions if carried out as part of a systematic or widespread attack against a civilian population. They include murder, extermination, torture, rape or other sexual crimes and ethnic cleansing.

War crimes involve grave breaches of the Geneva Conventions covering the conduct of war, such as deliberately targeting civilians, using chemical weapons, using child soldiers under the age of 15 and physical mutilations.

But an asylum seeker or an immigrant granted leave to remain who is then suspected of war crimes can mount a potentially successful defence to deportation if he or she would face torture or other serious infringement of their human rights on return.