There's nothing to legally challenge with "the government's pledge".
The only thing to challenge / claim unfair is a lack of consultation. They'll likely win and p&o likely have factored in the cost (90 days pay I think,).
Btw, anyone shopping at Primark today, or driving an MG or ......?
Nobody mentioned the Government’s pledge being legally binding. The challenge will be to show how the government actually stand on worker’s rights.
The big fines will potentially come for not completing a HR1 form. This is something they have no defence for not completing. The lack of consultation is another issue. The outcome of a tribunal may include rehiring.