I disagree. Think of the intentions behind the legislation!!
The thinking is, that by banning smoking within enclosed or substantially enclosed public spaces, that it will reduce smoking related diseases caught via passive smoking. Therefore, whether or not YOU (the individual) inhales or not is completely irrelevant. What is relevant is that the individual has ignited a substance that is toxic to others if inhaled by them.
Though I understand your argument that such a person would not in fact actually be 'smoking', the ignition of the tobbacco product is sufficient.
I have yet ro read the England & Wales statute, but Section 4 of the Smoking, Health & Social Care (Scotland) Act 2005, provides that:
"4 Meaning of �smoke� and �no-smoking premises� (1) In this Part, �smoke� means smoke tobacco, any substance or mixture which includes it or any other substance or mixture; and a person is to be taken as smoking if the person is holding or otherwise in possession or control of lit tobacco, of any lit substance or mixture which includes tobacco or of any other lit substance or mixture which is in a form or in a receptacle in which it can be smoked".
I think that's pretty clear. Holding a lit cigarette within an enclosed or substantially enlosed public space is breaking the law in Scotland. My guess is that the legislation in England & Wales strongly mimics that of Scotland before it, and the Irish Republic before the Scots.