The government no longer pays interest on this £375 billion of its borrowing, because to do so would mean that it would simply be paying interest to itself since the government gilts now belong to the Bank of England, which is in turn owned by the Government.
The gilts are still paying interest. Which the BoE turns over to the government as its profit. Sure, we can say that govt is thus paying interest to itself. But we cannot say that interest is no longer being paid.
We reiterate: this whole process can be undertaken without creating new debt that will have to be repaid in future. It is instead paid for by creating new money, which is a total different process.
Sigh. The creation of new base money has costs.