The parents of teenage motorcyclist Harry Dunn have spoken of their “terrifying” and “emotional” first court encounter with their son’s killer.

The Dunn family campaigned for over three years for Anne Sacoolas to face the UK justice system, which involved meetings with high-profile politicians and a trip to the White House.

After 45-year-old Sacoolas pleaded guilty to causing Mr Dunn’s death by careless driving on Thursday, the 19-year-old’s mother Charlotte Charles and father Tim Dunn recalled the “relief” they felt as she appeared on the screen at Westminster Magistrates’ Court in September.

Speaking about the first time the family saw Sacoolas in court, Mrs Charles told the PA news agency: “Walking towards court, there was still the apprehension of ‘is she going to appear?’

“Until it actually happened you can’t allow yourself to fully believe that it’s going to happen this time.

“We’ve been here before, it was meant to happen in January and at the 11th hour the rug was pulled from beneath our feet.

“We were strong as a family – we walked tall and proud, held our heads up high and just aimed for those front doors.

“Even sitting in the courtroom was terrifying.”

“It seemed to take forever for her to appear on that screen,” Mr Dunn added.

“It was probably the hardest time in the whole three years, that 12 minutes or 15 minutes waiting for her to appear.

“We could see other people on there (the video-link) but we couldn’t see her, the judge was coming out and I was thinking ‘is there a last minute technical hitch and they can’t get in?'”

Mrs Charles continued: “The link took a while to come up – they were 10-12 minutes late and it felt like hours.

“Our knuckles were blue holding on to each other, from gripping each other so tightly.

“And then when she did appear it was almost like, relief.”

“When she did appear, it was like ‘this is actually going to happen’…” Mr Dunn said.

Becoming emotional, Harry’s mother said: “If I wasn’t sat down I probably would have fallen down because for me it was like ‘OK, Harry – promise done’.

“So it was a good job I was seated.

“It was extremely emotional.

“I just didn’t take my eyes off of her on screen.

“I think I probably darted across to her lawyer once or twice – but I didn’t take my eyes off of her because I had no idea whether she could see us.

“But I needed to show those that have tried pretty damned hard to break me and us, they didn’t quite achieve it.”

The Crown Prosecution Service (CPS) initially announced that Sacoolas’s case would be heard in January, but the hearing date was vacated at the 11th hour to enable “ongoing discussions”.

Speaking about how she felt after the first court date was vacated, Mrs Charles said: “I had a massive breakdown. Yeah, complete meltdown. Nobody saw me for a week.

“It makes me upset now because number one, it was my birthday… and it was just going to be a nice quiet family day at home, and then to to get that news was just beyond devastating.

“I can’t even begin to describe the anger, the upset, the amount of tears that were shed. I was extremely angry.

Asked if she knew the reason for the delay, Mrs Charles said: “We still don’t know. We may never get to know.

“But there’s so many things that we have questions about and that’s going to be one of them. We’ll push for an answer on that.”

Mr Dunn interjected: “I’d just wanted to add as well… the other family members, my parents, it devastated them that day.

“They thought this was it, and to have it taken away with no explanation – it took my mum ages to get over it.

“When you’ve campaigned for so long and you think you’re there, and then for no reason it’s gone, and you don’t know when it’s coming back, it took ages and ages for people to get over it.”