yeah just to echo the previous post....you will get stung by customs!
how likely partially depends on the method of postage. If you pay for USPS express mail international, it will reach the UK faster but is handled by Parcelforce at the international Coventry hub (all international arrive there) and HMRC UK customs are straight on your case at the airport. If you do get flagged, not only will you have to pay import tax on the value of the goods but also on the P&P costs which is quite expensive, given the USPS EMS prices for heavy parcels.
Instead, opt for USPS global priority international; a slighter slower delivery method in comparison but is handled by Royal Mail once in the UK. They process this along with all the other regualr international mail (letters/parcels etc.) inbound for the UK so it is far less likely to be flagged by RM's customs division, if at all.
How do i know this? 2 sources:
1). HMRC customer service advice.
2). Personal experience: 2 orders from ansgear.com shipped via global priority international - no customs fess; 1 order from lasermygun.com via express mail international - stung by customs.
Customs are quite savvy these days and wont fall the "this is a gift" on the admin forms anymore. They'll charge you regardless if it is valued at >£40.
Obivously, you can undervalue your incoming package but it is illegal to do so and you also run the risk that should it get lost or damaged in transit, you can only claim for the (undervalued) amount.