The coroner at the inquest into Princess Diana's death is appealing against a High Court ruling that he could not allow paparazzi evidence.
The car carrying Diana was being pursued by photographers
That court had backed a legal challenge by the parents of Diana's driver, Henri Paul, over allowing the evidence to be read to jurors.
They argued that cross-examination would not be possible if the photographers did not appear in person.
Coroner Lord Justice Scott Baker has now decided to challenge the ruling.
Evidence in person
The photographers were asked to appear in person at the hearing, but declined - a move backed by the French government.
Lord Justice Baker decided their statements could be read to the jury, in order to allow the evidence to be heard - but this was overruled by the High Court.
Earlier this week, judges said the photographers' evidence had to be admitted by calling a witness - for example, someone who had taken down the statement.
Mr Paul died in the crash on 31 August, 1997, as did Diana's companion Dodi Al Fayed.
He had driven the couple, plus a bodyguard, from the Paris Ritz Hotel with paparazzi following, and crashed in the Pont de l'Alma tunnel.
On Friday the coroner's counsel, Ian Burnett QC, told the Court of Appeal that the Paul family lawyers, backed by the Paris Ritz Hotel, were seeking an opportunity to "examine witnesses as close to the horse's mouth as possible to enable them to explore the circumstances in which the statements were made".
Mr Burnett told Lords Justices Waller, Latham and Dyson that the High Court decision, if upheld, would "lead to illogical consequences and seriously disrupt these inquests and other inquests into deaths overseas".