I am very disappointed that a whole former UK Prime Minister does not actually know what ponzi schemes are. Or probably he does not know what bitcoin is. But at least he should know that there is nothing hidden about bitcoin investment like Ponzi scheme.
But he knows perfectly well how to throw parties during lockdown.

That's probably why he doesn't have time to study the basic principles of bitcoin and identify Ponzi schemes.

Stop taking the words of public figures as truth, because they are just power-hungry people who only know how to lie. And yet, it can’t be said that they are very smart.

In a ponzi scheme, investors money are used to pay earlier investors with the scheme not generating profit from any business, but the business owners will tell their investors that they are generating profit from a business which is a lie. Later the business can not go on and collapse.
There is an excellent example of a financial pyramid - this is a traditional pension fund, where money is paid to the "first investors" (retired population) at the expense of money from "new investors" (working population).
Bitcoin is not like this, nothing hidden, no business but just a coin that has a store of value. Bitcoin has been existing since more than 16 years, many people have profited from it and it is still a store of value.
As much as many may dislike it, in fact, bitcoin partially exhibits the characteristics of a Ponzi scheme (just like any stock in any company in the world), because early investors profited at the expense of later investors. In fact, the entire scheme is based solely on the belief in bitcoin's future growth, as that's precisely why investors invest in this asset (otherwise, why would they?). But the longevity of bitcoin's existence dispels any doubts about it being a Ponzi scheme, as no one Ponzi scheme has lasted so long.