The judge at Worcester said, apropos of what might be meant by a 'suitable' education:
In our judgement 'education' demands at least an element of supervision; merely to allow a child to follow its own devices in the hope that it will acquire knowledge by imitation, experiment or experience in its own way and in its own good time is neither systematic nor instructive.
The judge went on to say that such a course, 'would not be education'. He then ruled specifically that a child not receiving systematic instruction in mathematics and English, if it were capable of learning them, could not be said to be receiving a 'suitable education'.
And there you have the matter in a nutshell. According to this key piece of precedent, any home educating parent who is not actually teaching or instructing his or her child in mathematics, is not providing a suitable education in the legal sense. Any parent leaving her child to acquire knowledge in her own way and in her own time is not causing that child to receive a suitable education either.
The next time any home educators feel like quoting Harrison and Harrison V Stevenson, I do hope that they will realise that autonomous education was actually condemned by the judge in the case and that home educating parents who don't teach their children mathematics and English systematically, were told in no uncertain terms that they are breaking the law by failing to provide their children with a 'suitable' education.