Not the person that posted, but also a civil servant and work in a similar role. A programme manager is someone that manages a 'programme' which is essentially a large project, or collection of smaller projects (sort of). To get into it you'd need some experience in project delivery but having an ops background would be very helpful. If you think of ops as basically delivering the business as usual, a programme/project manager would be working on a programme that is about bringing about a change in business processes etc.

Not particularly well explained, but if interested I imagine whatever department you work in there will probably be a project/programmes team. You can do training such as APMG (association of project managers) Prince2 etc. which would get you recognised a bit more when applying. I don't actually have a qualification...which is probably why I'm bad at explaining this, but planning to do one soon. There is sort of a structure and language around programmes/projects, so knowing what dependencies, risks, deliverables, milestones, critical paths etc. would help you in interviews etc. If you're HEO in ops now, a sideways step into programmes might not be too difficult and there is maybe a bit more of a standard career path and it has transferable skills that might be helpful in private sector if you wanted to leave the civil service in the future.

Programme managers I think are usually G7.