International head of sourcing Alistair Maughan led the team acting on the deals, with support from partner David Skinner, of counsel Anthony Nagle and associates Jonathan Lea and Masayuki Negishi.
On the first of the deals the team advised HMRC as it restructured its IT services contract with Capgemini.
The new arrangement is expected to save HMRC approximately £110m a year through the modernisation and disposal of legacy systems.
The team advised NPIA on a project to boost the capability of its radio system for the London 2012 Olympics.
On the Tata deal the firm acted for the consultancy concerning its partnership with Cardiff Council to be its new technology provider.
Maughan said: “These three projects demonstrate the importance of long-term relationships, both between client and law firm and between the customer and service provider in an IT or outsourced services contract.”