TUPE applies if BMI is to be TRANSFERRED into BA. TUPE does not apply if the 100% share ownership of BMI is taken up by IAG, and IAG leave BMI as a stand-alone, and do NOT TRANSFER BMI into another company.
The information we have is that IAG will take 100% share ownership of BMI and that BMI will at that point become ..... BMI. As the day before it when it was under Lufthansa ownership. As when it was owned by Bishop and was taken over by Lufthansa. There is no link with BA at all, apart from maybe the brand in due course, until BMI is TRANSFERRED into BA.
In the meantime BMI is a stand-alone company owned by IAG, with employees employed on BMI contracts. I'm puzzled as to how IAG can simply scrap a BMI contract and exchange it for a Vueling type one? What's to stop them then issuing BA pilots a Vueling type contract? Or Iberia pilots an Iberia Express type contract?