I'm no expert on law - as you've probably worked out by now! - but I think that there ought to be a degree of common sense applied to law or, to be more precise, how the law is applied.
As usual this summer as with every summer, the RMT and their obnoxious leader, Bob Crow, have a grievance. I'm not entirely sure what this grievance is nor do I care - as I understand it they've been offered an decent pay rise while most of us in the private sector are making do with nothing or an actual cut, but Crow and his cronies want guaranteed jobs for life - which is ridiculous.
What I do know, though, is that unions have adopted this tactic over the last decade of having short disruptive strikes rather than indefinite strikes until the grievance is addressed. It's obvious why they do this - it means minimal disruptance to the lives of the union members while maximising disruptance to the employers and, in the case of the tube, the general public.
Now I'm all for the right to withdraw you labour if you feel you have a genuine grievance, but my argument would be that should you decide to return to work for any reason then that implies acceptance of the conditions offered. Otherwise why would you return to work?
I don't know what the best way of encoding that in law would be - I would suggest that it should be made illegal to strike more than once over any issue thereby making it impossible for anyone to have a number of strikes of fixed length.
What is certain is that these tactics of short disruptive strikes repeated over weeks or months have become more common in the public sector. It's time they were stopped. They can strike until some agreement is reached or they can go back to work and accept the conditions offered - they should not be allowed to have their cake and eat it.