"... the dismissal of an employee by an employer shall be regarded for the purposes of this Part as having been unfair if the reason for it (or, if more than one, the principal reason) was that the employee - (a) was, or proposed to become, a member of an independent trade union, or (b) had taken part, or proposed to take part, in the activities of an independent trade union at an appropriate time. ..."
"... The applicant's performance at work had not always been satisfactory and Mr Hiscock complained to him about this on many occasions. Whenever those complaints were made his attitude was acceptable in that he agreed to do better. He was moved to other jobs because of his deficiencies. He had a tendency to take off odd days. He says he always notified the respondents when he did this but we prefer the evidence called by the respondents on this issue and find that he did not do so. He received a written warning dated9 December 1988 which reads as follows:-
"We find his evidence in this respect unconvincing. He says that the respondents set him this work to catch him out. We are not convinced that this was the case. We are influenced in this respect by what happened on18 September 1989 . Our impression is that by this time the applicant was failing to perform his work satisfactorily."