Krajisnik is one of the most senior figures to have been tried at the ICTY
A former Bosnian Serb leader convicted of crimes against humanity in the Bosnian war has been sent to the UK to serve his 20-year sentence.
Momcilo Krajisnik, 64, was jailed for the deportation, forcible transfer and persecution of non-Serbs in the war.
A 27-year term was cut when convictions for murder, extermination and persecution were overturned on appeal.
The UK takes Krajisnik as part of support for the International Criminal Tribunal for the former Yugoslavia.
Krajisnik, a former speaker of the Bosnian Serb parliament and close aide to ex-Bosnian Serb leader Radovan Karadzic, was sent to Britain on Monday, the tribunal (ICTY) in The Hague said.
He founded the nationalist Serbian Democratic Party with Karadzic and later became president of the Bosnian Serb Assembly.
Krajisnik was jailed in September 2006 for crimes against humanity, but in March had seven years cut from his sentence after some of his convictions - including murder and extermination - were overturned.
A Foreign Office spokesman said: "The UK is committed to providing practical and political support to the work of the international criminal tribunals, as part of our policy to combat impunity for the perpetrators of the most serious crimes of international concern.
"The transfer of Krajisnik to the UK under the UK/ICTY Sentence Enforcement Agreement is another example of the practical support we give - he will be the third ICTY prisoner to serve his sentence in a UK jail."
Karadzic faces 11 charges of genocide, war crimes and crimes against humanity for his role in the 1992-95 Bosnian war which claimed about 110,000 lives and displaced millions.