From an article in the Sun:
“His extradition, which was approved by Home Secretary Sajid Javid, was the first time a UK citizen has been extradited to Antigua to face criminal charges.
The Antiguan authorities said they would hold him at the old naval base because his lawyers said the notorious 1735 national prison in Antigua was inhumane.
It is not clear where Martin-Cramp will serve his sentence and his lawyers are expected to request that he do so in the UK.”