UK-Extended Layout
Microsoft Windows XP SP2 and above provide the UK-Extended layout that behaves exactly the same as the standard UK layout for all the characters it can generate, but can additionally generate a number of diacritical marks, useful when working with text in other languages (including Welsh - a UK language). Not all combinations work on all keyboards.
acute accents (e.g. á) on a,e,i,o,u,w,y,A,E,I,O,U,W,Y are generated by pressing the AltGr key together with the letter, or AltGr and apostrophe, followed by the letter (see note below);
grave accents (e.g. è) on a,e,i,o,u,w,y,A,E,I,O,U,W,Y are generated by pressing the backquote (`) [which is now a dead key], then the letter;
circumflex (e.g. â) on a,e,i,o,u,w,y,A,E,I,O,U,W,Y is generated by AltGr and 6, followed by the letter;
diaeresis (e.g. ö) on a,e,i,o,u,w,y,A,E,I,O,U,W,Y is generated by AltGr and 2, then the letter;
tilde (e.g. ã) on a,n,o,A,N,O is generated by AltGr and #, then the letter;
cedilla (e.g. ç) under c,C is generated by AltGr and the letter.
These combinations are designed to be easy to remember, as the circumflex accent (e.g. â) is similar to a caret (^), printed above the 6 key; the diaeresis (e.g. ö) is similar to the double-quote (") above 2 on the UK keyboard; the tilde (~) is printed on the same key as the #.