The family of a young woman who died in a hit-and-run crash in Qatar are urging the Foreign Office to press the Gulf state for the release of all available evidence.
Raffy Tsakanika, from Cambridge, died after the car she was travelling in as a passenger was struck from behind by a second vehicle near Doha in March 2019.
At an inquest last year, the coroner criticised the Qatari authorities for the lack of information provided.
The second vehicle, which was travelling at "excess speed", caused the first to lose control and overturn in the four-lane carriageway, and the second vehicle did not stop at the scene.
Qatari national Mubarak Al Hajri was sentenced in Qatar to two months in prison over the crash and ordered to pay compensation to Ms Tsakanika's family.
Rishi Sunak must suspend Dominic Raab during bullying inquiry says union chief But at a UK inquest last year, the coroner criticised the Qatari authorities for the lack of information provided to the inquest.
Afterwards, Ms Tsakanika's parents wrote to Foreign Secretary James Cleverly asking for a meeting.
They have since received a written response from Foreign Office minister Lord Ahmad of Wimbledon in which he extends his "sincere condolences" for their loss.
He said that the British Embassy in Doha had requested documentation from the Qatari authorities.
But he continued: "In our experience, it differs from jurisdiction to jurisdiction as to what the relevant local authorities are willing or able to share with UK coroners."
He said that officials in Doha could seek written confirmation from Qatari authorities that Al Hajri has served his prison sentence if the family wanted it.
Radd Seiger, the spokesman for the 21-year-old hairdresser's family, described the situation as "entirely unacceptable."
He said: "In the circumstances and the highly critical remarks the coroner made at the inquest in December, this is an entirely unacceptable response from the FCDO when we had requested to meet with the Foreign Secretary James Cleverly, who has handled the case personally."
"This is yet a further example of the FCDO treating British citizens, living in Great Britain, and who are being oppressed and abused by foreign governments, like dirt on the bottom of their shoe."
He said Ms Tsakanika's family "deserved to get the very best diplomatic muscle", but instead got "barely a whimper while the Qatari authorities were doing their best to kick Raffy's embarrassing death under the carpet in the lead-up to the World Cup."
He called on ministers and senior officials to go back to the Qataris and "insist that the evidence that they clearly have" is disclosed to the family and the UK coroner so consideration can be given to a fresh inquest.
Last year's inquest was told that speed cameras captured Al Hajri's car, apparently undamaged shortly before the collision and damaged shortly afterwards, but these images were not provided to the UK coroner by the Qatari authorities.
Mr Seiger said: "The FCDO must no longer stand on the sidelines while this wholly innocent British family suffers beyond imagination.
"They deserve to know how Raffy died so that they can begin to process her death."