Under a 1970 Hague convention, to which the US and the UK are both signatories, the lawyers would ask the British courts to question him, through a “letter of request”.
London-based lawyer Peter Binning said the letter of request “would need to be executed by an English court”.
He added the letter of request would be made by the “central authority of the requested state”, in this case most likely the US State Department through a US court.
“Essentially it is a court to court procedure,” he said.
It is most likely her legal team would have to file these requests to the US court considering their case. The request may then be passed by the judge to the relevant foreign legal authorities.
However, according to guidance published by the US department of justice, American attorneys may actually make these requests directly.