More likely, IBM will install a standard COTS banking software platform, migrate data where they can, and declare success. If account balances match, that will be enough. Desired functionality, either for internal users or customers, will be secondary.
And that's probably what TSB should have done from the beginning, minus the IBM involvement. That hasn't worked well historically, based on the number of lawsuits against then for failing to deliver contracted systems.
(a quote from a different article).
This guy is an absolute joke. Just because you want something fixed quickly doesn't mean it's gong to happen. Bringing in an outside team is already a REALLY bad sign, but demanding an outside team to get up to speed and to implement a complete fix in two days? Yikes.