The witnesses
32.I heard evidence of fact from Markus Karwin, a development engineer employed by Nissen, regarding the prior disclosure of the Nissen Board. Mr Karwin gave clear answers to all questions put to him. 33.The two other witnesses were experts. Gary Knight gave evidence for Nissen. He was from 1997 a traffic management operator for Trek Highway Services Limited working on signs used on roads in London. His principal job was to drive an impact protection vehicle (‘IPV’). Mr Knight’s subsequent employment included a period at Mervyn Lambert Plant Ltd where he was involved in a project for Nissen in 2012 to design signage for mounting on an IPV. Mr Knight was a very good witness who was careful as to the subjects about which he could state an opinion and those about which he could not. 34.Dr Hans Meseberg was Horizont’s expert. He has over 40 years’ experience in traffic signs and lighting. Between 1972 and 2006 he worked for the German Federal Highways Research Institute and was either a member of, or chaired, committees of DIN (the German Standardisation Institute), FGSV (the German Road and Transportation Research Association) and CEN (the European Committee for Standardization). Since 2006 Dr Meseberg has been a freelance consultant. Dr Meseberg was generally a good witness, although occasionally keen to argue Horizont’s case. 35.Because the qualifications and experience of the two experts differed, the matters on which they could give authoritative evidence did not completely overlap. Unlike Dr Meseberg, Mr Knight knew about the practice of those working in the UK in relation to road traffic signs, including the terms used at the filing date. Dr Meseberg’s background meant that he knew more about the design and qualities of traffic signboards.