The union plans to install surveillance cameras on its picket lines to catch illegal agency workers and will erect signs saying: 'Smile. You are on camera when you cross this picket line'.
The GMB claimed that a statement last week by JJB founder and chairman David Whelan indicated that the company 'plan[s] to use agency staff to do the work of strikers'.
It has written to three Wigan-based employment agencies telling them that if they will be risking a£5,000 fine per worker and possible legal action from the union if they supply replacement staff to JJB during the strike. The union claims that doing this would contravene the Conduct of Employment Agencies and Employment Business Regulations 2003.
It said that its picket-line cameras will catch JJB using any illegal agency workers and evidence will be used in any subsequent court cases against the employment agencies.
The GMB revealed yesterday that 266 of its members would strike next week after refusing an offer of a 3 per cent pay rise from JJB. GMB regional secretary Paul McCarthy said that JJB was trying to 'run a coach and horses' though employment regulations and the GMB would 'mount a vigorous campaign to expose these illegal plans'.
Whelan has taken over responsibility for the pay negotiations from chief executive Tom Knight. However, further progress on any deal appears to be unlikely after Whelan left for the Caribbean yesterday for a three-week holiday after labelling the union negotiators 'communists'.
A source close to JJB said that the accusations by the GMBN were 'totally unfounded' and that the company was 'taking a very strong line on this'.
The source added: 'JJB will never break the law. Any implication that they would is simply not true. [However] if they have already got agency workers then they will carry on using them [during the strike].'