Not necessarily illegal. As BA owe £3b in debt then there may be scope to sell off assets to repay the debt. Thereby leaving nothing much left of a company to declare insolvent. If nothing else you could move all the existing troublesome BA employees into a wholly owned subsidiary which you could soon declare loss making.
Michael O Leary would have no difficulty in sorting this out under existing UK employment law.
Lets face it. Sour faced buttie slingers, pilfering bag chuckers and dim witted passport checkers are hardly irreplaceable professionals deserving of well perked jobs. Each one can be replaced with less than a weeks training and be on a no-strike contract.
BEN