Customs/tax on iphone bought in USA, being brought into UK?

I'm going to Florida in June and was hoping to buy an iPhone while there.

It would be an unlocked non-contract GSM phone (same as used in UK).

It costs £699 here or $699 there - working out to approx £530 if I buy in the US.

Aside from any state taxes I need to pay there, will I be charged customs or tax on the phone when I bring it back to the UK? It will be the one phone, for my own personal use (not business or selling etc).

Does anyone have a definitive answer with back up proof? I don't want answers like 'google it' or 'check hmrc website' etc as I have done all of that and still have no clear answer. If you can't answer the question asked, please don't respond.

Technically you should pay duty on it, however if you just take it out the package and carry it in your pocket they'll never know.

As per other post. Just ask for uk chargers, if you are a heavy phone user consider a contracr instead.

I used to be a Customs Officer. There will be duty and VAT to be paid on import. VAT is 20% and duty of about 10% on top. Do not be tempted not to go into the RED channel on re entry to UK. Customs these days are not thick and if caught it may well be seized so pay $699 and keep nothing?