Actually, what Sir Pollard is saying is different. He's saying delta is so efficient that everybody, including the vaccinated, will eventually be exposed to the virus and likely get infected. So because transmission is impossible to prevent (short of a New Zealand-style zero COVID strategy), there is no such thing as strict herd immunity (against any infection).
But the current data shows that the vaccinated who do get cases are largely in the mild category, and seldom in the severe COVID category. The vaccines are doing exactly what they were designed and tested to do. In other words, you and I may ultimately get infected by the virus but it will likely be an asymptomatic or mild ca se. Once enough of a population is vaccinated and/or post-infection, the pandemic shifts to endemic. You're beginning to see a consensus that wealthy nations with successful vaccination programs will reach this next spring. Some may even reach it sooner, such as Denmark.
The key thing is that the end goal is to reach a lower level of viral transmission, and a much lower level of severe cases. It's very hard to get there without good vaccines. Anybody claiming Sir Pollard is claiming otherwise misrepresents his statements IMO. The Brits are absolutely not arguing to end vaccinations at this point.
The problem for the U.S. is when you drill into the data, you'll find that we're basically two wholly separate tribes across a large geography. The Northeast and a few western states have a high vaccination rate, and relatively low levels of severe COVID. But look at red states (or counties) and you see pathetic vaccination rates that barely move up over time. I know it's a cliche by now, but referring to it as a "pandemic of the unvaccinated" certainly fits the evidence.