MI5 was monitoring a teenager who took her own life after being groomed by a far-right American extremist and arrested on suspicion of terrorism offences, an inquest has heard.

At 15, Rhianan Rudd was the youngest person charged with terror offences in the UK, but the prosecution was later discontinued.

She was 16 when she took her own life on 19 May 2022.

A pre-inquest review hearing was told MI5 gave intelligence to police – but that it had no further involvement in Rhianan’s arrest and charge.

Rhianan, who was born in Essex but moved to Derbyshire in 2012, was a looked after child at the time she died.

She was detained in October 2020 for downloading a bomb-making manual and charged with various offences the following April.

The teenager, who had autism, was due to stand trial in March 2022, but charges were dropped in December 2021 after evidence emerged she had been groomed by American extremist Christopher Cook.

A BBC investigation, published last year, found evidence showing grooming and sexual exploitation of Rhianan was handed to MI5 months before she was charged.

At Chesterfield Coroner’s Court on Friday, Edward Pleeth – counsel for the inquest – said in July, solicitors wrote to interested persons, which includes the Home Office, the chief constable of Derbyshire Police and the Crown Prosecution Service, to update them on the case.

“MI5 confirmed that they provided the police with intelligence in the course of the police investigation of Rhianan Rudd,” he said.

“MI5 did not take the decision to arrest or charge, or the subsequent decision to discontinue the prosecution.”

A full inquest is set to start from 26 February next year, and is currently estimated to last for about three weeks.

The court heard about 600 files have been passed to the coroner as evidence, totalling about 17,000 pages.

Jesse Nicholls, representing Rhianan’s family, called for the extent of MI5’s monitoring to be discussed as part of proceedings.

He told the court she was “a child who died in circumstances involving an exceptional period of state involvement leading up to her death”, adding the public interest in examining the state’s role “is compelling”.

“It appears she was monitored by MI5 while being subjected to online exploitation,” he said.

Neil Sheldon KC, representing the Home Office including MI5, said: “We accept you will be scrutinising sensitive material very carefully to see what if any information was known about the risk of self-harm or suicide, and what if anything was done in respect of that information.

“We maintain that this is not a case in which it is necessary to assess the substance of the underlying intelligence collected by MI5.”

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