There's no point spending £3BN on IT, rather than returning the money to your shareholders, unless you make your current IT situation better. To do that, you need to do ALL of the following things:
1) Stop outsourcing. All of it.
2) Stop offshoring. All of it.
3) Cut half of your IT hierarchy. If you don't show as the lowest two wrungs in the corporate structure diagram then you should have a 50/50 chance of being employed on Monday.
4) Hire a few permanent staff that actually understand software development, code architectures, the cloud, and networking.
5) Send a memo to all staff stating in plain speaking that you are no longer a bank. You are a technology company that handles banking deposits. The real value isn't in your management chain or board of directors. The real value isn't in your front office staff. The real value is in your IT staff.
Getting IT right isn;t hard, you just need the right people and the right plan. The first step forward is to understand that today, you have neither.