If you google it, revenue is at £8 billion (Office for Budget Responsibility) and in decline, and NHS spending is at £2.6 billion in England, so the bulk of it (NHS England).
I do not have the specific info/ref to hand, but at one point some years ago, smoking brought in something of the order of nine times as much into the NHS as it spent on smoking related illnesses. I was very surprised by this.
Even so, the NHS's goals are rightly such that greatly reducing the harm done by smoking is preferred over keeping this revenue. Unlike a tobacco company that would not factor harms external to the organisation into the profit and loss calculation.