Honestly, I feel that's quite an unrealistic stretch and not really conducive to a constructive conversation.
I want my medical history to be analyzed, especially in aggregate of everyone else's: to find anomalies, develop new medications, advance science, better understand the genome, and a myriad other "positive" outcomes that come from a system like this. I don't care if the NHS builds their own data crunching system or they contract it out to someone else (although in this case I'd lean towards preferring someone else with a track record in ML already, e.g. a leader like Google) -- what's most important is the medical advances that are all but guaranteed to come from it, not the potential threats that could come from its potential misuse.
It can be argued that Google, specifically, is too biased to handle the data (in which case, it sounds like they just need to be more transparent with how they're using it). It could be argued that it could fall into malicious hands that would blackmail or do "evil" things like raise premiums (to which transparency and security are, obviously, very important). It could be argued that the chance of misuse outweighs the chance of it doing any good, and so on. Those are good arguments, and address vulnerabilities in a system that shares extremely private data, and each concrete criticism opens up the conversation to how to improve the approach. Just saying it'll be like 1984 isn't very helpful to argue. How will it be like 1984? How can we address that?
If technology can be used for good _and_ bad, we put checks in to make sure it's used for good and not used for bad; we (as a species) don't avoid creating it altogether. Transparency, security, accountability, verifiability, etc are all problems we've solved in similar situations throughout history to make sure a system benefits everyone, even when there is a risk of bad players. I assume you have a bank account, even though a bank manager could just bag up all the money and walk out with it any day (or not).
Not to be cliche, but: with great power comes great responsibility. Utopian goals like "solving disease" are always going to come with the risk of someone misusing some new panacea-enabling technology to spread an even worse disease. We should be making sure technology is properly checked and balanced so we can actually use it to do good, not fighting technology (or advancements in health or technology) from existing in the first place because of fears of "what if".