The MP representing the family of Harry Dunn has urged the Government to block any “expansion” at the US military base at the centre of the teenager’s death.

Former business secretary Andrea Leadsom secured a debate in Parliament on Thursday in which she said two planning applications submitted for RAF Croughton should be refused until suspect Anne Sacoolas returns to the UK.

The base, near Brackley in Northamptonshire, was due to welcome a further 1,300 staff in 2015 after the proposed closure of RAF Alconbury and RAF Molesworth in Cambridgeshire, until the decision was reversed in 2018.

In August last year, 19-year-old Mr Dunn was killed when his motorbike crashed into a car outside the base – with Sacoolas claiming diplomatic immunity following the collision.

Now, Conservative MP for South Northamptonshire Mrs Leadsom has urged the Government to “call in” applications to update the communications facility – including plans for a new entrance to the base and two new domes covering radar equipment.

Concerns had been expressed about the base in the past – including a “possible read-across by the media to rendition flights” which was raised in a briefing note to then parliamentary under-secretary of state for the Foreign Office, Lord David Triesman.

The note, dated July 2006 and titled “US request to increase staff at RAF Croughton”, reads: “While members of the House (of Commons) show interest from time to time in the US Visiting Forces based at RAF Croughton, there has been no recent interest in the Regional Information Technical Centre (RITC).

“However, given the nature of this issue, the fact that RITC is a telecommunications relay facility, and the possible read-across by media to rendition flights, if it became public there could be some limited media and parliamentary interest.”

Responding to the document, a spokesman for the US State Department told the PA news agency that US operations at Croughton do not facilitate air operations.

Following the latest planning applications proposed for RAF Croughton, Mr Dunn’s mother, Charlotte Charles, wrote an open letter to MPs in which she said: “It is all the more upsetting that rather than sitting down with us and working out how this situation is going to be avoided again, it appears to be the case that what is uppermost in the US Government’s minds, so soon after Harry’s death, is to bring forward plans to expand their operations at the base.

“It has upset us all terribly and caused outrage in the community.

“It is the height of arrogance for them to think that it can just be business as usual and shows the contempt they have for us as a nation and how little they really think of the importance of Harry’s life.

“Well, he was important. We are all important despite what they think.”

Speaking in Parliament on Thursday, Mrs Leadsom said: “The fact is, Madam Deputy Speaker, that if you or I unintentionally killed someone by driving on the wrong side of the road, we would face the UK judicial system – one of the best in the world, designed to deliver justice to victims and fairness to perpetrators.

“We are just not making any progress in achieving justice and closure for Harry – it is now six months from the day my Right Honourable Friend, the Home Secretary put in the request for extradition and almost a year that Harry’s family and friends have been trying to deal with their unimaginable loss.

“There have recently been planning applications submitted on behalf of RAF Croughton to South Northamptonshire Council to presumably begin the work on their expansion.

“Speaking frankly, Madam Deputy Speaker, it is unthinkable under the circumstances that any planning applications from the base can be treated as business as usual between two long standing allies.”

Mrs Leadsom continued: “Many constituents, other people right across the country and even from the United States itself have written to me to say, ‘So if I, or a member of my family, is driving or walking near the base, and an American citizen harms or kills us, that person can simply go back to the US and there’s nothing the UK can do about it, even though the USA is our greatest ally and one half of a special relationship?’

“It is utterly intolerable.”

Concluding her speech, Mrs Leadsom said: “In my view, and in that of many residents of south Northamptonshire, it is essential that the Secretary of State calls in any planning applications that could leave my constituents vulnerable to future tragedies.

“I know that my colleagues in Government share my desire for justice to be done and to prevent any repeat of this terrible tragedy.

“It seems to me that for any potential expansion or changes to be agreed at RAF Croughton, we need our greatest allies, the United States of America, to demonstrate their empathy for this devastated family by allowing justice to be done for Harry.”

Responding to Mrs Leadsom, Communities minister Luke Hall told MPs: “I want to be clear from the start that there are no plans to increase the number of personnel on site at RAF Croughton. The decisions taken under the previous US administration in 2015 have now been reversed.”

He added that “any new US proposals to expand at RAF Croughton would require the agreement of the UK Government”.

Mr Hall said: “There are two proposals to update some infrastructure on the site, including upgrading the main gate and renewing technical equipment within the current base perimeter, both of which the US have stated they deem necessary regardless of the future strategic plans for the base.”

He continued: “Our national planning policy framework, for example, states that planning permission may be refused where there is an unacceptable impact on highway safety – and again, this of course applies whether that decision is taken by the Secretary of State or by the local planning authority.

“And we are confident that the concerns of local people and any evidence of risks will be fully taken into account when considering any current or future planning applications.”