It looks like going into sematics here again, but the SVR is a misnomer then. It should have been defined as “standard arbitrary rate” or “semi-fixed” or something. “Variable” in Webster dictionary is “able or apt to vary, subject to variation or changes.” Any reasonable person understands that rate changes are driven by funding costs, what else? Tracker mortgage is simply a version of a variable mortgage type where changes are linked explicitly to the external rate that in turn determines those funding costs. Hence many people in this forum who lost their trackers cite their contracts where "variable rate" and "tracker rate" were used interchangeably, and confusingly, by banks themselves.
When taking the SVR mortgage I queried the mortgage officer on the differences between SVR and a tracker, and what “discretionary” in the contract stands for. He said the difference was legalistic and that SVR and trackers always co-varied in the past. My solicitor said the same thing. I know that the SVR contract if read verbatim implied any rate whatsoever but this is not how the mortgage was explained or perhaps understood by the bank officials themselves at the time. I don’t know if they were telling the truth but you could also see in any timeline graphs that SVR and trackers did co-vary in 2000s, trackers were lower but they went up and down together, with lags. So on the one hand you have a contract with an arbitrary rate, but on the other hand you have verbal assurances that the rate is not arbitrary. I know one goes with the written contract but the market economy is also based on trust.
Ultimately it would be nice if only fixed or true variable contracts (explicitly linked to something, or fixed at the interval, like it is 3% now but can not go higher than 1.5% over the mortgage lifetime) were offered and remained. SVR gives too much discretion that the banks abused.