I am Mike Thompson, Head of National Fingerprint Training for Centrex, a Home Office department responsible for training the UK's police service.
I am a fingerprint expert with more than 32 years of experience as an operational expert and as a regional bureau head before taking up my current job.
After watching Panorama's Fingerprints in the Dock, I feel it is my responsibility to reassure people of the confidence they can have in the fingerprint service.
Thank you for all of your excellent questions. Let's start with Phill Callway from Sheffield who emails, 'I was always told that no two sets of fingerprints are the same. Is this no longer the assumption?'
And Dave Munday from Northamptonshire asks, 'Whilst it is unlikely for two people to have the same fingerprint what are the odds for two people to have the same points of identification and appear, for identification purposes, to be the same fingerprints and the same person?'
Skin falls into two types - smooth skin which covers the majority of the body and friction ridge skin. Friction ridge skin extends from the fingertips to the wrist and from the tips of the toes to the heel and each area of friction ridge skin is unique to that person. So fingerprints are undoubtedly and irrefutably unique to the individual. They are even unique to the finger, thumb or area of palm print of the person.
This understanding comes from scientists working in embryology, genetics and anatomy. They have observed that friction ridge skin starts to develop on the embryo and foetus in the womb from about the sixth week of pregnancy. By the 24th week the body's development has finalised its blueprint with unique fingerprints for life.
B Logie from Aberdeen asks, 'Surely experts only need to find one point of dissimilarity to prove that two prints are not the same to exclude a suspect from an enquiry?'
Identification by fingerprints is done by firstly analysing the mark found at a crime scene and then comparing it against the images on a fingerprint form. The analysis is crucial to gather all the information contained in the mark. This includes the type of fingerprint pattern, arch, loop or whorl, the particular type of pattern within each of those families, the ridge flow that those patterns take, the formation of the ridge features on the ridges themselves and with the use of greater magnification it is possible to see the unique positioning of sweat pores on the ridges or the unique shapes of the edges of the ridges.
Only when the information gathered from the analysed mark matches, in all of these features, with the impression on the fingerprint form will an expert be satisfied with the identification.
It is highly unlikely that there will only be one 'point of dissimilarity'. There will be many dissimilarities when two impressions are not made by the same digit.
John Lewis from the UK asks, 'Where do experts receive their training and qualifications and are they totally independent from the police authority?'
Every police force in the UK has its own fingerprint bureau staffed by trained and competent fingerprint staff.
The training of fingerprint experts is my responsibility. They undergo a rigorous training programme lasting several years.
In the UK, fingerprint experts are trained and qualified by Centrex National Training Centre which is independent from any police force. We also train many overseas fingerprint officers.
In Panorama's Fingerprints in the Dock, Michael Mansfield QC made a good point with which I agree. He said that the police service should evaluate the fingerprint service.
Of all the forensic disciplines, the fingerprints service is leading the way in transparency, accountability and accreditation.
The fingerprint service itself recognised several years ago that in order to reassure the courts of the continuing credibility of fingerprint identifications and the reliance that could be placed on them, the service must review practices, procedures, audit of bureau performance, the training of staff and the maintaining of standards.
The service is answerable to the National Fingerprint Board which is chaired by a chief constable and made up of senior operational police officers, Home Office representatives and very senior forensic practitioners. This board has the remit from the Association of Chief Police Officers (ACPO) to review and evaluate areas such as standards, performance, training and personnel within bureaux and has established working groups to review these areas of operation. Should any recommendations come out of these groups, then the National Fingerprint Board can and does mandate compliance throughout the service. This ensures best practice is inherent throughout the service and that our ultimate aim is achieved which is to benefit the general public by preventing and detecting crime by the use of accurate and reliable fingerprint identifications.
The National Fingerprint Training programme is fully mandated by ACPO and ensures that all fingerprint officers must follow the same path of training and development from day one up to expert status.
The training has been evaluated and the assessments ensure that competence is fully proven before a fingerprint officer can be recognised and registered as a expert.
Beyond this stage there is an on-going process of continuous improvement and development and regular competency testing to demonstrate continuing practical competence by the expert.
A fingerprint expert can also formally register on an independent forensic register which requires a regular re-accreditation of procedures and practices.
This model has been recognised by other forensic disciplines as the means by which practical competence can be assured in the workplace and that common standards and best practice of operation are improved and maintained.
Onto an email from William Leary from Edinburgh, 'I was a fingerprint officer at Scotland Yard during the fifties and sixties. I still remember the words of the chief inspector who ran the training class when he said careless work by one fingerprint officer could well undermine the long held acceptance of fingerprints as an infallible method of identification. Do you agree?'
There is a corporate responsibility on all fingerprint officers in their duties and which is ultimately to the public.
Emer Ronayne from Waterford in Eire, 'Are all prints prepared as charts to be reviewed by juries? If not, why not?'
Visual aids for the court include various methods of enlargement and explanation and are used if required to fundamentally demonstrate to the court the identification process. I wholeheartedly agree with another point made by Michael Mansfield QC in the Panorama film. He said that any expert should be able to explain to the court the basis for their findings. This obviously includes fingerprint experts. Our training makes clear to the fingerprint officers that their first duty is to the court and to explain in easily understood language how they reached their findings.
And onto some more of your questions.
I'd like to take two questions together. The first is from Dave Lorde, Faversham, 'I've heard that there has been no scientific study done to establish the degree of confidence that two individuals in a large population, such as the UK, share a print whether this means having 16 clear points of correspondence or any other criteria. Is this correct?'
The second question in the area is from John Flemming, Scunthorpe, 'When I was training as a police cadet in 1970 we were told that the chances of two people's fingerprints being identical were about one in 5,000,000,000. Forces nationwide were worried about what they would do when the population (which was then around 3,912,000,000) reached that figure, and fingerprints would no longer be 'proof' but merely 'corroborative' evidence. The population is now more than 6,000,000,000.
Is that it then?'
The research we have comes form the studies I've described in my answer to Phil Callaway and David Munday. It has nothing to do with population figures.
David Hay from Glasgow, 'Why have the jails not emptied with successful appeals over fingerprint IDs?'
I think the courts can rely on the accuracy of the fingerprint identification process and they can be further reassured by the application of proper and continuously audited evidence.
Nick, London, 'Can DNA be retrieved from latent fingerprints? Can you tell how old a fingerprint is? Do fingerprints contain any unique chemicals?'
The use of DNA is now commonplace in crime scene investigations and minute amounts retrieved from various body fluids can produce sufficient DNA samples. There is no reliable way to accurately age a mark. Sweat deposits are the main source of fingerprints found at crime scenes and contain various chemicals excreted by the body.
A Southee from High Wycombe, 'Surely modern powerful computers could be used to verify fingerprints? As one expert said its just black lines.'
Fingerprint computers are used only as an aid to the searching process, they do not produce the identification. That is down to the skill and competence of the operator.
Next question is from Jackie Boothman, Clitheroe who tells me her story, 'I visited New York and had to be fingerprinted. When I came back into the US at Detroit one month later I was held up at immigration. I eventually demanded to know what the problem was as they kept fingerprinting me. They told me that I had the same index print as someone else. I asked if I would keep having this problem when I entered the US and they just shrugged. Is this just a US immigration computer misreading or a case of identical prints?'
Unfortunately I cannot comment on the systems used by the US immigration service. But you cannot have the same fingerprint as anyone else. No two people can have the same fingerprints.
Leslie Rose, UK, 'If fingerprints can be lifted from articles using tape, then it stands to reason they can be transferred to another area and re-used at a different scene of crime. True or false?'
Crime scene marks are frequently lifted from articles by crime scene investigators or scenes of crime officers and then immediately secured on a clear plastic sheet and endorsed by the officer at the scene. These procedures are in place within all police forces. It is important to establish proper and auditable continuity of evidence to prevent any print being transferred to another surface.
Julian Corner from Whitby, 'Is it possible to take DNA from the fingerprint itself? This would be a failsafe to match the DNA and the fingerprint' and I'd like to answer this along with this question from David from Biggleswade, 'I thought that DNA fingerprinting was being used as it is much more reliable than ink fingerprints. There is a 1 in 1 billion chance of an error in the science of DNA analysis. Why isn't DNA fingerprinting isn't being applied as the standard in court cases?'
The problem with all of this is that identical twins share the same DNA. They do not share the same fingerprints.
Lindsay, Manchester is interested in a job in fingerprinting and she emails, 'I would like to study fingerprinting at crime scenes. Do you do a university course or do the police force offer a training course for forensic science?'
Many universities offer forensic courses which if you were to gain a degree could assist with employment as a crime scene investigator in a police force. However, you would still require practitioner training in the discipline of crime scene examination at Centrex National Training Centre.
And finally a good question from Laura Marcus, Staffordshire, 'Government plans to introduce compulsory identity cards and a database to back them up is a truly terrifying idea. If we can't rely upon fingerprints being accurate, how can we use them to prove our identities?'
The simple fact is that fingerprints are unique and are a reliable way to establish identity. Thanks again for all of your questions.