Ms Khanom was discharged from the jury during the trial

Ruhela Khanom, in her 20s, was accused of hiding an MP3 player and earphones beneath an Islamic hijab or headscarf.

She was discharged at the Blackfriars Crown Court trial of Alan Wicks, later jailed for life for murdering his wife. The attorney general has decided not to refer the matter to the High Court because of insufficient evidence.

A statement from the office of the Attorney General, Baroness Scotland, said she had "considered carefully the papers in this matter, in particular the witness statements, and has concluded that there is insufficient evidence to provide a realistic prospect of proving beyond reasonable doubt any alleged contempt of court".

Jury service

Ms Khanom was discharged by the trial judge, Judge Roger Chapple, after the prosecutor Peter Clarke QC claimed the juror had not been paying attention while the defendant was in the witness box giving key evidence.

Having looked very carefully at this case at the heart of is this whether this lady deliberately ignored the evidence

Judge Aiden Marron QC

When jurors misbehave

Wicks, 72, was later convicted of bludgeoning to death his wife, Pamela, at their home in Hayes, west London, after taking out £150,000 life insurance.

At the end of the trial, it was also revealed Ms Khanom had repeatedly tried to avoid jury service.

During the trial, Judge Chapple warned her after she appeared to be doodling on a pad while evidence was being read out.

'Tinny music'

Mr Clarke initially asked for her to be discharged, but the judge resisted, saying jurors could only be discharged for "very, very serious and improper behaviour".

But the following day one of the defence lawyers thought she spotted a wire under the hijab.

JURY SERVICE People under 18 and over 70 are not eligible Every year 185,000 people in England and Wales do jury service In the past doctors, lawyers, vicars and politicians were excluded from jury service Nowadays the only people excused from jury service are the mentally ill and those who have served custodial sentences

Later the judge said he had thought he could hear "tinny music" during the trial but dismissed it as his imagination.

The trial judge referred the matter to Judge Aidan Marron QC who considered the matter earlier this month.

Judge Marron said: "The police have investigated this matter and assembled a file.

"Having looked very carefully at this case at the heart of is this whether this lady deliberately ignored the evidence.

"That means that she was listening to music during the course of the evidence.

"Although there may be allegations she was persistently late and was quite indifferent to listening to the evidence and studying documentation... these matters demonstrate mindset but do not constitute contempt of court.

"The fundamental allegation is whether she was deliberately ignoring the evidence by listening to music."

A Ministry of Justice spokeswoman said: "The attorney general has taken the decision not to prosecute based on the evidence before her. But there have been instances in the past of jurors doing inappropriate things and having been penalised for it."

She said the law was tightened a few years ago to reduce the number of people able to excuse themselves from jury service.