From the Law Society:

There is no advice on avoiding jury service.

I've spoken with Professional Ethics, who confirm, as a civic duty it overrides everything. The rules recently changed and solicitors can now be called up for service. Members may speak with the court clerk if they are unable to do it, only thing that will definitely get a member out of jury service is an identifiable conflict of interest. Note, there is no leniency with the supervision rules in the code, members need to make sure that the office is supervised when they are out of the office in accordance with the rules.

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