In the UK about 97% of debit payments are made through the Visa network so for ‘instant’ payments it’s really a monopoly.
This acquisition provides MasterCard with access to real-time payments (FPS) and peer to peer mobile instant payments in Zapp (plus Bacs & Link).
The PSR complain that the banks own the company that runs the infrastructure so it has to be sold off. Who’s going to buy it? Can’t be another bank as there would be complaints of unfair advantage for that bank over the other users of the system. Could be FDI, but that also implies monopoly.
This is what happens when a regulator wants the government to think they are relevant.
Also, at a global level, UnionPay is larger than Visa and MasterCard.