The Radio Shack that I remember was the name of the American parent company that ran the Tandy shops that were once all over the U.K. It's a pity that they are no longer around as I used to spend hours browsing through all their electronic goodies and most of my model railway switches and wire were bought from them.
Maplins have tried to fill the void left by Tandy but personally I don't think they are as good. For example the last time I went into a Maplins store I could only buy lead-free solder !!! ......and that conveniently brings us back to where we started
