Foreign Secretary William Hague has welcomed news of Qatar's new leader as a “historic day”.
Sheikh Hamad bin Khalifa Al Thani announced that he has transferred power to British-educated crown prince Sheikh Tamim bin Hamad Al Thani in a long-anticipated move which puts a new generation in charge of the Gulf nation.
The 61-year-old emir revealed the news in a televised address today.
Mr Hague said: "I wish to thank His Highness Sheikh Hamad bin Khalifa Al Thani for the friendship and support that he and the people of Qatar have offered the United Kingdom under his leadership.
"Our relationship is stronger than ever and the British Government looks forward to enhancing them further under the leadership of His Highness Sheikh Tamim bin Hamad Al Thani."
He added on Twitter: "Historic day for Qatar as the new generation takes over."
Sheikh Tamim, 33, is likely to begin the process of putting together a new government that may be in direct contrast to the old guard leaders across the Western-backed Gulf Arab states.
There has been no official explanation for the decision, but it is widely believed the Sheikh Hamad is suffering from health problems, the Associated Press reported.