I reckon over-broadly worded legislation straying well beyond centuries-old legal limits parading ministerial authority as due process of law and under-scrutinised by Parliament is a dangerous thing.
I also reckon that possibly the notion that a warrant could be served on an individual and binding on a telecoms provider may have been intended to allow someone to collar a bloke driving an Openreach van and tell him, as a representative of a telecoms provider to put a tap on a given line without going through too much paperwork. I further reckon that even if that's the case it's open to misuse far beyond that.
Hang on a minute. A warrant is not and never has been an order, instruction, something compelling. It is permission to act in a way that would otherwise be illegal, those actions being judged a necessity to advance a specific investigation by a minister and/or judge and/or someone else duly empowered to make such decisions. It is not served on anyone, it is given to someone.
The dictionary definition of a warrant is "a document issued by a legal or government official authorizing the police or another body to make an arrest, search premises, or carry out some other action relating to the administration of justice". The key word is authorise; there's no compulsion.
An ordinary policeman who wants to enter a property needs a warrant, but once it has been obtained they're not actually obliged to bust down the relevant door. AFAIK the only way someone can be compelled to do anything is by direct order from a high court judge (or greater), but that's a very different beast to a warrant.
If a warrant were an irrisistable order, there'd be no need to specifically mention telecoms companies in the acts. They are mentioned because a warrant is simply permission, not an order, so the act has to specifically state that telecoms have to help out with the warrant.
I don't see why anone would collar a wireman out on the streets - I'm pretty sure that the networks are more nationally reachable than that. And, strictly speaking, a warrant is basically the only paperwork that someone needs to take an action that would otherwise be illegal. And it's not going to be carte-blanche to do anything, it's going to very specific.
I think that this whole thing has come about because whats-his-name has misunderstood what a warrant actually is. If one considers the act in the context of a warrant being permission (specifically permission for someone who can and wants to assist to actually provide that assistance), and not an order, the wording makes a lot more sense and is far less 1984 than whats-his-name has been making out.