Defence worker breached Official Secrets Act by allegedly 'leaking' details about UK missile system

A former defence worker breached the Official Secrets Act when he allegedly leaked details of a UK missile system "upon which the security of the realm partly depends", a court has heard.

Software engineer Simon Finch denies recording and disclosing secret defence information and refusing to give authorities access codes to three electronic devices, the Old Bailey heard.

The 50-year-old, of Swansea, is accused of sending technical details classified as "secret" and "top secret" in an October 2018 email containing operational information about the weapons system, which is still in use by the armed forces, his trial heard on Tuesday morning.

An expert damage assessment found that the release of the information could give "a hostile adversary of the UK... an understanding of the function" of the system and "methods of countering it", prosecutor Mark Heywood QC told jurors.

The systems analyst worked for private contractors including BAE Systems and QinetiQ from the late 1990s until 2018.

He appeared for his trial on Tuesday morning wearing a mustard-coloured jumper and tinted spectacles.

Opening the prosecution case, Mr Heywood told jurors: "Simon Finch is 50 years old and a British citizen. He shares British nationality with the other key participants in this trial.

"Unlike most of us, for many years he occupied a very important and special role as someone with expert technical ability.

"He was employed in the design, testing and configuration of a UK weapons system on which the security of the realm partly depends.

"Suffice it to say the system in question is a UK missile system still in use by armed forces of this country.

"The document he attached to the email set out technical detail classified as secret and top secret... (and) contained detail about the operational performance of the system to which I have referred.

"A full damage assessment has since been carried out to find consequences or possible consequences of that information being disclosed into the public domain.

"Expert evaluation has concluded that the release of information of that kind, for example to a hostile adversary of the UK, would give them an understanding of the function of that relevant system which in turn would allow them methods of countering it."

Mr Heywood said the disclosure could create a "risk to the UK and to others with whom that technology is shared".

Jurors will hear more details about the system during closed sessions of the court, with journalists and the public not allowed into those proceedings.