The problem with going the extra mile

TBagpuss

I think the problem with the policy was that it didn't include anything at all about what to do if a shoplifter became violent. It basically said 'it you think they might be violent, don't approach them at all, if you think it's safe, approach them, invite them to go with you to the back office and then given them a banning letter or call the police"

So the policy of not approaching them couldn't apply, because by definition they have already been approached because they didn't appear to be threatening, and there was no policy to say what to do in that scenario.  the only reference in the policy to any use of restraint was to say that staff shouldn't use restraint to get the shoplifter to the office - there was no advice at all about what to do if a shoplifter became violent after they were in the office, and the policies did not forbid the use of reasonable force in self-defence or defence of others.

The tribunal found that the employer had no reasonable grounds to believe that the employee had broken any policy, they then also found that even if the employer had been reasonably able to believe that, dismissal was outside the range of reasonable responses in the circumstances. 
The tribunal judgment makes for an illuminating read
I don't think it was a case of loopholes, it was a case of the employer having not created appropriate policies or indeed appropriate safeguards for staff, and then seeking to sack an employee rather than address the issues with their management. 
(the tribunal also heard evidence that tesco chose not to use security guards, despite knowing that the store was dangerous, and claimed that this was not on finacial grounds(!)  and that the procedures for reporting incidents were so complex that no one understood or was able to use them)