You would indeed assume so..

However they have assumed differently.. they have most likely been mislead by the telecoms provider into thinking that it's a "local rate" number..

Non the less, it's worth reporting to NHS England.

They have nhs.net provided e-mails.. so they must have a connection to the NHS somehow

Of course the points being made about the NHS and contracted government services are totally correct and fair.

In my view, the only case in which it is legitimate to use a 084 number is if the Service Charge can be justified and is properly declared. That cuts out the vast majority of the public sector, the voluntary sector and, without any question whatsoever, the NHS.

My point is that, given that ACECIC perhaps do not understand the mistake they are making, the first (and perhaps the only necessary) step to resolving the situation could be approaching them directly with helpful advice.

ACECIC has contractual relationships with a large number of NHS bodies in respect of the various services that it provides, some of which (e.g. the GPs) are accessed directly using geographic numbers. Rather than picking one's way through a complicated network of rules, regulations and Guidance and engaging involved formal complaint procedures, it may be simplest to go directly to the heart of the problem, in the first instance.

I do not normally comment on engagement with bodies in this forum, so I will leave it readers to work out for themselves what action I have taken. If anything worthy of public report emerges, I will share it.