Power adaptors

Hope this helps - it's a comprehensive list, as well as photos:
http://www.worldstandards.eu/electricity/plugs-and-sockets/
http://www.worldstandards.eu/electricity/plug-voltage-by-country/

You need the BS 1363 plug for the British Isles and the CEE 7/7 plug everywhere else (for devices without earthing a CEE 7/16 "Europlug" is sufficient). Check whether your equipment is 240V compatible. I wouldn't bother to bring anything which isn't, as all of the stuff you need as a traveller can be purchased for little money in Europe.

A FAQ. Read:
https://www.ricksteves.com/travel-tips/phones-tech/electric-adapters-converters

If you electronic power unit is rated for 110-240 volts and 50/60 Hz, you just need plug adapters to connect your North American plugs (two parallel flat blades which may or may not be polarized, or grounded plug with the two flat blades plus round conductor) to the UK three thick flat blades for London and the "continental" two round conductors for the other three cities.

The simple answer for power/heat devices (e.g. irons) that are only rated at 110-120 volts is don't bring them.

What exactly do you mean by a power adapter. If you simply mean a mechanical plug adapter, the ones mentioned above will suffice. If you mean a voltage converter, that is a different device altogether.

Devices that are multi-voltage, ie, have an input specification of 100-240 VAC 50-60 Hz (which are most electronic devices), will work on European power sources in the UK and on the continent; you will only need the correct plug adapter. However, if they only say they are for an input of 100 up to 125 VAC, they will not work without a voltage converter. You are better off to find something that does not need a voltage converter than to lug around a converter.

US devices with a polarized plug (one blade wider that the other) have safety features that only work on polarized power. Most European power is not polarized, so the safety features will be lost. Leave such devices at home.

thomas,

As Lee mentioned, it would help to know whether you're referring to Plug Adaptors or Voltage Convertors. What type of devices are you planning to travel with?

You'll need one type of Plug Adaptor for London and anywhere else in the U.K., and a different type for use on the continent. Some additional information would be helpful.

Thank you all for your comments and help.
I just need the simple adaptors, not the power converter.
I have it all figured out now.
Thanks again for your help.
Tom

All I ever use the power adapter for is charging my iphone, so I only need a USB port. I have one of those multi country adapters, which works ok, but I have found out that I can't use the phone while its charging, a nuisance when trying to stream Netflix or whatever late at night. It's also quite bulky. I ended up buying an inexpensive (and small) adapter, like the kind you get with the iphone in Spain and it worked great. I'm just knocking myself for not picking one up in London, for the UK version.