In American English is the symbol # usually called 'the pound sign' ? If so, what is the symbol £ called ? I accept that Americans may have little use of it; traditional typewriter keyboards in Britain did not have the $ sign, after all. Still, # is used for numbering so is '#7' , to be typed using the digit, dictated as 'pound seven' ?

In Britain the key is called 'the hash key'; the symbol # is called 'a hash (sign or mark)'. The use of # for 'number ' is unknown except where addressing goods for export to the US or in similar circumstances.It has become understood here because Japanese exporters use it in literature such as instructions and guarantees . It may become more popular as it is quicker and easier to type than 'No.'; that is, once the whereabouts of the hash key is established !

"A pound of hash" Wow Fred - You really know how to get attention!

In American English, yes # is often called "the pound sign," especially when referring to a telephone keypad. I have also often heard it called "the number sign" (especially BEFORE automated phone calls became so widely-used).
I've never taken dictation, but I myself would simply say "number seven" and expect it to be typed "#7." And yes, this sign is very common stateside as the symbol for "number."

As for £, we call it "pound(s)" too, since that's what it stands for. However, the symbol is not on American keyboards, so I have to type the symbol by holding down the Alt key while typing 156.

PS - I don't think I realized that # was "hash mark." (Thanks for filling me in on that! ) I used to hear that term used now and then when I was young, but that's been quite a while now...

T -I-E, My sudden interest in this comes from a new book, 'Mighty Fine Words and Smashing Expressions' by Orin Hargraves (Oxford University Press; ISBN O-19-515704-4 ).I hope it appears in the US.

The author, an American lexicographer, may have set out to explain differences in usage, punctuation or words e.g 'trunk' for 'boot' (of a car) but the book is far more. It covers differences in government,foodstuffs, music, sport, newspapers and even media cliches and more from a cultural as well as a linguistic point of view .

It would certainly help some contributors to AP; one innocent called The Observer 'a trashy tabloid '( it's one of the most serious UK Sunday papers,founded in 1791 ). I see our lot can innocently make much the same mistakes and false assumptions about the US and life there .

At least I don't think I'd describe an American woman as 'homely' any more ( here it only means 'kindly, sympathetic' or 'good in domestic matters'depending on context )!

PS Anyway, isn't 'a pound of hash' a pound of chopped or minced (=ground) beef with potatoes ?