20-23 February 1990 A liaison meeting took place between British and French during which the French scientist Claude Calisti was shown PT/35(b) but could offer no assistance or suggestions. See document D8924 in appendix of protectively marked materials.
According to Langford-Johnson’s police notebook (prod 1766, pages 8-9), on 4 February 1991 he and Williamson went to the Central Explosive Lab in Paris with a view to showing photographs of the timing device MST-13 to senior forensic scientists and to see if the device was known to them.
The notebook records that they spoke with Claude Calisti, who said he “was aware of the line of investigation being undertaken in relation to PT35 having been at an earlier briefing on 28.2.90”. Presumably this in fact relates to the meeting on 20-23 Feb 90.