The UK Government enacted the introduction of the TPD last April, in time for the EU regulations to start on May 19th 2016.
Any product manufactured before November 19th 2016 (tanks, liquid, etc.) can still be sold until May 2017. After this date, tanks can be no larger than 2ml, must be "child proof" and leak proof. No liquid can be sold above 20mg/ml (so in reality, 18mg/ml) or be sold in volumes above 10ml per bottle. You can still buy 100ml but you will receive ten 10ml bottles. And all products must have warnings on them about nicotine being "highly addictive" - even if the product doesn't actually contain nicotine! (tanks).
You can still buy mods. And if the manufacturer of a tank offers an extension kit to increase the capacity you can use that but it has to be sold separately.
Wire/cotton/batteries are not affected by the regulations.
The biggest problems are: If you DIY you will no longer be able to buy nicotine solution in the usual strengths of 54mg/ml or 72mg/ml (stockpile!). Or, if you prefer to vape 24mg/ml liquid you will have to drop to 18mg/ml. (Oh, and the environmental cost of all those extra bottles! They want to "protect the children" don't mind messing up the planet in which they will live in...
Because the TPD is already part of the UK statute, even after we have left the EU, until it's repealed - it's the law (and don't expect it to be high up on their list).
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