​change your name to Sam full of misinformation.
why do you think you can go to poundland and take a blurred photo of anything random you can afford, stick that on here as a deal, when its a pound or less all the time, then hunt for someone else's deals to spread misinformation about,
is it because your jealous?

That's not true, all AC-DC convertors draw a small idle current when no load is attached.

There are some USB wall sockets that detect if no items are plugged in and switch off the power but this doesn't look to be one of them.

If anyone has a CPC nearby
http://cpc.farnell.com/pro-elec/2213u/2-gang-switched-socket-with-usb/dp/PL14985

Or if you want 3 .... screwfix http://www.screwfix.com/p/lap-13a-2g-sp-switched-socket-2-1a-2g-usb-charger-white-pack-of-3/1122p

Expect to be told it is useless as it's not 3.1 volts despite the price. Also expect to be told it is unsafe as you can't switch the USB off.

Also waste of electricity if cannot turn off

If nothing is plugged into the USB port it is NOT using electricity, there is no load/resistance to generate a current flow.

Twin pack £11.99 at Argos

They can waste electricity if badly designed - just like some badly designed plugin chargers (not so much nowadays, but was much more common)

There are also safety issues with some of them (eg. general poor construction, poor separation between mains and low voltage side, poor design of the LV side). Hopefully not with decent brand products, but I'd be very wary of cheap ones, no name one etc. juts like I'm very wary of cheap plugin chargers (one got extremely hot and plastic deformed, one started buzzing and fell apart). It's really not worth it for saving a few quid.

And in a few years when it's all USB-C they will be annoying :-)

Used to be vaguely concerned about the waste of electricity leaving chargers plugged in (not enough to really do anything about it, but still...) - until EDF came and fitted the smart meter last week - now we have a readout of our current use in pence per hour... of course did the standard thing of going round turning things on and off to see what uses what.

Turns out that our night time use, with 3 fridges, 3 TVs, a couple of radios, and a monitor on standby, a laptop "sleeping" but active, 2 printers on standby, android box, fire stick and 2 chromecasts plugged in, 3 active baby monitor cameras plus receiver, a small nightlight, and lastly at least half a dozen chargers plugged in (that I can think of)... with all that going on, our use is... 1p per hour. I'm well aware it all adds up, and that's £90ish a year, but I'll happily pay that not to run around switching all that stuff on and off at the plug every day.

Other appliances are something else entirely of course - we've become allergic to the tumble dryer in the space of a week (24pph!), the microwave isn't as popular as it once was (19pph), the oven gets turned off the second supper is done (lots pph), and watching the monitor while boiling the kettle has almost ruined my morning cuppa!

​Haha, that's on the cooler "synthetics" setting - I haven't checked what it is on "cottons" yet!