Foreign Secretary Dominic Raab will meet the parents of a British teenager killed in a car crash involving an American woman who was granted diplomatic immunity.
Mr Raab will meet Harry Dunn's parents, Charlotte Charles and Tim Dunn, at 4pm at the Foreign Office in central London.
The foreign secretary met the US ambassador to the UK on Tuesday to request the return of Anne Sacoolas, who flew to the US after the fatal crash in Northamptonshire in August.
Police believe Mrs Sacoolas, 42, pulled out on to the wrong side of the road as she emerged from RAF Croughton - a US spy base - on 27 August.
Detectives told Sky News that Harry Dunn was riding his motorbike on the correct side of the road at the time of the collision.
The 19-year-old suffered multiple injuries and died later in hospital.
Speaking to Sky News hours before going to meet Mr Raab, Mr Dunn said: "We hope she's going to be coming back for justice for Harry."
Mrs Charles added: "We're very much hoping for some positivity, some good news.
"If we don't get the answers that we want we're going to take the next steps but it's not in anyone's best interests, including hers.
"So we're hoping we get a positive this afternoon but if we don't we'll sit with lawyers again and we will make that plan to go forward."
In a statement on Tuesday, a Foreign Office spokesman told Sky News: "The foreign secretary met with the US ambassador today and urged the US to reconsider its position and do the right thing by Harry Dunn's family."
There have been questions over whether Mrs Sacoolas should have been granted diplomatic immunity as her husband, Jonathan Sacoolas, does not appear on a list of registered diplomats.
The Foreign Office insisted he was an accredited diplomat in the eyes of the British government, therefore his wife was entitled to diplomatic immunity.
Harry's parents told Sky News on Monday they want Mrs Sacoolas to return to the UK to face them, criticising her for leaving the country.
They said they did not "necessarily" want her to be punished.
Mrs Charles said: "Come home, come back to the UK. We're not a horrible family, we're a usual UK family that just need to put a face to what we have now is a name.
"Talk to her, find out how she's feeling. She's got to be suffering as well, she's a mum.
"Without knowing who this person is properly we can't begin to try and start our grieving process.
"We just don't understand from one human to another, one mum to another, how you could just get on a plane and leave behind the devastation she has without even speaking to us, without an apology of any kind?"
She appealed for Boris Johnson to use the UK's "special relationship" with the US to "its full potential" to get Mrs Sacoolas to return to the UK.