Lots of comments about how dangerous E-cigs can be, for reasons that aren't actually valid a) in the UK and b) if people use legal, unmodified equipment and liquids.
All e-cig liquid sold in the UK contains only 4 substances:
Nicotine (not actually required, you can buy 0 nicotine liquids)
Flavourings - reputable companies only use food standard flavourings, and you don't NEED to add this
VG (vegetable glycerine) - commonly used in many products such as soaps, toothpaste, beauty products, as a sweetener in foods
PG (Propylene Glycol) - commonly used in things like Medical products used orally, injected or as topical formulations, toothpaste (again), beauty products (again)
All these are things we use daily in many ways, and though yes they are heated up they aren't combusted so minimal chance of any toxins being created like they are in traditional cigs, car engines, some power stations, bonfires etc. There is nothing in an e-cig liquid that can't be bought in one form or another in most supermarkets.
The most common causes of batteries blowing up or melting used to be people using the wrong chargers - not all chargers are equal and e.g. an iPhone charger would charge at a much faster rate than the older e-cig batteries were designed for & could cope with. Batteries have been improved over the years, so now the most common cause is people using black market batteries that aren't compliant with UK safety standards.
Oh and the flavours and colours aren't particularly aimed at children, as they are just as likely to attract adults. I'll have a puff on my fruit or sweet flavoured e-cig rather than eating chocolate or sweets if I get a craving, and I love the different colours the batteries come in and accessorise my clothing.