The expert explained that whilst Mr Thompson was an intelligent and literate man, he was socially naïve and it would not have occurred to him that suspicions would be raised in other people's minds about his continued association with children or his conduct of bathing and drying them.

The second expert, who had extensive experience in the field of autism and Asperger’s syndrome, assessed Mr Thompson using Module 4 of the “Autism Diagnostic Observation Schedule” (ADOS). She noted that his most significant impairment appeared to be in the reading of emotions expressed by others. She observed that he had lifelong difficulties in developing social relationships, especially with his peer group. His lack of emotional understanding, she said, would make him seem, at times, callous or selfish because he would be unaware of the impact of his behaviour on others.

Both experts observed that Mr Thompson did not readily make eye contact.

The second expert said that when she interviewed him he also displayed a "rather pragmatic style of answering, lack of facial expression and monotone intonation".

Mr Thompson, in evidence, admitted an innocent association with the children but said that the accusations were entirely false. The defence case presented to the jury was that two of the boys were suspected of viewing child pornography on a computer in their home and that, when interviewed by the police, first one and then the other attempted to blame Mr Thompson for introducing them to the material. The police had examined his computer and no such material was found.

It was submitted that, despite their denial, the children were aware of Mr Thompson’s arrest in 2006 and of the rumours circulating and the allegations made against him. They, the defence argued, had used Mr Thompson as a soft target at which to deflect blame. Some lies told by the boys were exposed in evidence.

The judge explained to the jury that if they considered there was evidence of conspiracy between the boys to deflect blame from themselves to Mr Thompson by telling lies about him, they should conclude that it would be unsafe to convict him of any offence.

Mr Thompson’s previous convictions, including the 2007 convictions, together with the evidence found on his computer relating to the Sri Lanka under-age rent boy websites were admitted as evidence during the trial.

At the end of the trial the jury found Mr Thompson not guilty upon all counts.

Having been found not guilty Mr Thompson applied for permission to appeal the convictions handed down at the first trial in 2007. Permission to appeal was granted and in 2014 his appeal was heard by the Court of Appeal.

Relying upon the fresh expert evidence Mr Thompson argued that had the jury been aware in 2007 of the diagnosis subsequently made, and of the evidence later given by the experts to the jury in 2012, they may have formed a different view both of himself and of his actions.

Allowing the appeal, the Court of Appeal said that the fact that Mr Thompson was acquitted in 2012 did not in itself mean that his convictions in 2007 were unsafe. However, it concluded that the expert evidence upon which Mr Thompson relied in 2012 was both relevant and of some probative importance to the issues considered by the jury in Reading in 2007.

The jury in the 2007 trial, it said, was very much concerned with the issue of interpretation of Mr Thompson’s alleged conduct, partly admitted and partly denied and it was for this reason that the expert evidence was relevant. It could not be said that had the jury in 2007 been aware of the expert evidence the decisions they made would have been the same and for this reason the Court of Appeal concluded that the verdicts were unsafe and must be quashed.

The Court of Appeal said that there were three respects in which it was satisfied the jury may have been assisted by the expert evidence.

Firstly, one of the boys had protested that it was unnecessary for Mr Thompson to wash and dry him so thoroughly. The Court of Appeal said that a person like Mr Thompson who was rule-bound and somewhat obsessive about personal hygiene might not be sensitive to any expression of the boy's resistance. It also said that he might not have attached any significance to the fact that the boy had an erection.

An allegation that he had smacked the boy’s penis, which was denied, if true did not, the Court of Appeal said, mean that it took place as an expression of sexual excitement. It could have been boyish stupidity or inappropriate discipline. These were issues to which the expert evidence could, depending upon the jury's view, have been significant.

The Court of Appeal agreed with the direction given by the judge to the Aylesbury jury that the diagnosis of Asperger's syndrome was relevant to the questions: (1) what Mr Thompson did and (2) with what intention he did it.

Secondly, in relation to a count of sexual assault where it was claimed that Mr Thompson had inserted his finger into one of the boys’ anus and moved it, the Court of Appeal said that it was not possible to determine from the evidence what it was, if anything, that may have convinced the jury that the touching was sexually motivated. The Court of Appeal said that for this reason it could not exclude the possibility that, had the jury been aware of the admitted features of Mr Thompson’s Asperger's, they would have reached a different conclusion, either as to the nature of the act or as to its purpose.

The Court of Appeal also said that there was not in their view any marked distinction between the allegation made in a count of sexual assault by penetration for which Mr Thompson was also convicted and those made in respect of other boys subjected to the same treatment. The Court of Appeal said that the jury's conclusion that Mr Thompson had committed a sexual assault probably educated their view of sexual motivation relevant to the more serious count of sexual assault by penetration.

Thirdly, the Court of Appeal noted the tendency of Mr Thompson, during his evidence at the Reading trial, to pick arguments with the prosecutor over comparatively trivial detail, while failing, unless re-directed, to confront the underlying and critical question. In the Court of Appeal’s opinion, the expert evidence would have been of value to the jury in determining whether, on the one hand, Mr Thompson was “evading the question or, on the other, that he was, as a result of his unusual traits, reluctant to be deflected from his pre-occupation with matters of detail”.

In relation to Mr Thompson’s explanation for his search for under-age rent boy sites in Sri Lanka, the Court of Appeal said that expert evidence would have been “informative” both in assessing the content of his evidence and the manner in which it was delivered.

An argument that during the Aylesbury trial Mr Thompson demonstrated himself to be a calculating witness, quite capable of trimming his evidence to suit the case, even if right, did not, the Court of Appeal said, mean that he was undoubtedly lying to the Reading jury about the lack of sexual motivation for his actions.

This case highlights the significance of expert evidence in cases involving individuals suffering from Asperger’s syndrome.

One Psychology has expert psychologists who are able to provide assessments and report in the diagnosis, assessment and treatment management of those with Autism Spectrum Disorder.

Email us at ask@onepsychology.co.uk for further information