Home Secretary Theresa May has signed an order for British businessman Shrien Dewani to be extradited to South Africa over his wife's murder.
Care home owner Dewani is accused of arranging a hit on his bride Anni during their honeymoon in Cape Town last November.
He now has 14 days to appeal to the High Court against his extradition, a Home Office spokesman said.
Mrs May's decision came after District Judge Howard Riddle ruled at Belmarsh Magistrates' Court in south-east London last month that Dewani, 31, should be sent back to South Africa to stand trial.
Suspicion fell on him after Mrs Dewani, 28, was shot dead when the couple's cab was hijacked in the dangerous Gugulethu township.
Taxi driver Zola Tongo, who has admitted his part in the crime, claimed in a plea agreement with prosecutors that Dewani ordered the carjacking and paid for a hit on his wife. Dewani, who is said to be suffering from severe post-traumatic stress disorder, denies any wrongdoing.
Mrs Dewani's uncle, Ashok Hindocha, said: "We are very happy about this decision. We were expecting this but we weren't expecting the decision to come this early.
"It shows that finally the system is working and we're happy that this can come to a closure."
The Hindocha family handed in a petition to the Home Office last week, imploring Mrs May to ensure Dewani was extradited.
Dewani standing trial is the only way they can get the answers they need, they say.
