Usual disclaimers, 2005, polls etc - https://www.theguardian.com/uk/2005/aug/22/july7.terrorism - breakdown by party/class/gender/age and the support is the same (+/- tiny margin).
I dont think you really need further specifics - years later without bombs going off I expect, with no further explanation to those polled needed, that the 70/30 split would probably be the opposite direction.
That "some" is the problem. People who say they support the tradeoff often change their minds when the specifics are explained to them. This happens all of the time in polling and even rigorous studies. Subtle changes in phrasing and context completely change results.
We're seeing that right now. There was a survey done on college campuses on the phrase "from the river to the sea". many endorsed it, until they were shown a map of the region such that the specific meaning became clearer, and then a lot of them changed their minds.
This sounds more like manufactured consent than the will of the people. Plus, I don't know if this happened with Blair's measures, but across the pond, the Patriot was initially written to be sunset after 4 years (from 2001), but wasn't fully sunset until 2020! This was long after the majority of Americans in polls said they didn't want to trade civil liberties to fight terror.
https://news.gallup.com/poll/183548/americans-say-liberties-...
was right there with you until the very end. people seem to confuse the fact that members of congress that are elected by the people do things on behalf of those people. this isn't a situation where the transitive property from math can be used. for example, if A elected B and B did C does not mean A wanted C