Why does my pound sign (£) mysteriously change to a hash (#)?

In the olden days (!), we used to type letters on something called a “typewriter”. The lever you thumped was embossed at the other end with the character that appeared on the paper when the embossed end struck a ribbon that inked the paper. The key ALWAYS produced the same character because that was what was on the other end of what you struck. There is no such necessary and permanent relationship between the key you tap on a computer keyboard and what appears on the screen. Instead, there is software (ie computer programming) that intercepts the “keystroke” you tapped and passes on an instruction to the operating system. So, if you hit the key marked “a”, the software (often called a “keyboard file”) would pass on the instruction that a letter “a” is to be displayed on-screen.

So, there is no necessary, physical, connection between the key you tap and the character that appears on-screen. It all depends on how the active keyboard layout file (the software mentioned in the previous paragraph) “maps” the keys. So, the keyboard mapping for a UK layout will produce a pound sign (£) when “shifted 3” is depressed but the keyboard mapping for a US layout will produce a hash (#) when “shifted 3” is depressed.

If you always get a # when you want a £ then the wrong keyboard layout is being loaded when you start up. To load a UK keyboard at boot time:

Windows 10

• Click on “start”
• Start typing “region” (without the quotes)
• Click on “Region and Language Settings” when this choice is offered
• If “English (United Kingdom)” does not appear under the heading “Preferred languages” then click on the plus sign (add a language), type “English” (without the quotes) into the search box and then select the correct version of English
• If “English (United Kingdom)” does appear but is not the first item in the list of installed keyboards, then click on it and then click on the upward pointing arrow to make it go to the top of the list. Note that you can uninstall any unwanted keyboard files by clicking on them and then clicking on “remove”. Windows computers tend to be shipped with English (US) as the default keyboard. You have to add the English (UK) keyboard before you can delete the US one.

Mac

• Open System Preferences (the apple at the top left of the screen)
• Open Keyboard
• Click on “Input Sources”
• If you don’t see the keyboard you want in the left column, click on the “+” and then select the desired keyboard to add it
• Click on the (newly added) desired keyboard in the left hand column
• Reboot

Now, the question I get asked from time to time is “why has my £ sign just started typing a # sign”. It doesn’t do it every time you start up (so you don’t need to re-select it as the default keyboard). It just seems to do it at random.

The answer is probably that you have accidentally issued a shortcut that instructs the system to change the current keyboard layout. On a Windows computer, this combination is the lefthand “alt” key with the “shift” key. It doesn’t give any feedback: it just switches the keyboard. If you see the characters “ENG” near the bottom right of your screen, this indicates that you have an English keyboard loaded. However, it doesn’t tell you the difference between English (UK) and English (US). If you click on this though, you can see which is currently selected and, if desired, click on the other one. You can also change keyboards with the Windows key and space.

On a Mac, you can probably see a flag on the top line of the screen, indicating the keyboard in use. Click on this to select a different installed keyboard. The shortcut to changing keyboards on a Mac is user-definable. To see the current shortcut (and change it if desired):

• Open System Preferences (the apple at the top left of the screen)
• Open Keyboard
• Click on “Shortcuts”
• Click on “Input Sources” in the left column and then view/change the shortcut in the righthand side of the window.

For more information, see this Wikipedia article on British and American keyboards