§ Miss Maynardasked the Secretary of State for the Home Department why his Department has discontinued the use of the Griess reagent in chemical forensic tests for the presence of nitroglycerine traces on hand swabs.
§ Mr. Giles Shaw[pursuant to the reply, 1 August 1984]: Griess reagent continues to be used to a limited extent by the Forensic Science Service in conjunction with a number of other techniques for the detection of nitroglycerine on hand swabs.
§ Miss Maynardasked the Secretary of State for the Home Department what are the reasons for the changes made in his Department's guidelines on the experimental and laboratory procedures to be followed in the collection and analysis of hand swabs from people suspected of having had contact with nitroglycerine since 1972.
§ Mr. Giles Shaw[pursuant to the reply, 1 August 1984]: The technique of collection of nitroglycerine by hand swabbing has been modified to improve the efficiency of recovery of such material. Techniques used to analyse recovered material have been modified as new, more sensitive analytical instrumentation became available from manufacturers.