Does "let alone" here mean "but not"?

When one thinks of what half a billion pounds could have been spent on in the NHS, let alone around the world, one has to be pretty scathing about that decision."

Quote:

When one thinks of what half a billion pounds could have been spent on in the NHS, let alone around the world, one has to be pretty scathing about that decision."

When one thinks of what half a billion pounds could have been spent on in the NHS, (let alone) NOT TO MENTION around the world, one has to be pretty scathing about that decision."

When one thinks of what half a billion pounds could have been spent on in the NHS, OR EVEN around the world, one has to be pretty scathing about that decision."