“Developing the new intranet cost Â£15k. The monthly hosting, support and iterative development cost is in the hundreds of pounds per month, less than a tenth of the monthly hosting cost of the intranet it replaces.”
see Intranets: DCMS doing it right | Government Digital Service.
Chuckle. If you read the comments on that blog post you find that previously the IT department were afraid of the security of WordPress, used on tens of millions of web-facing sites…
Sometimes top-down leadership is needed to break log-jams and catch the wave.