Okay, it’s a pet hate, but it’s still wrong, and you really shouldn’t do it.
This is the ampersand: &. It is stylised from the Latin word for and, which is et.
It has very specific uses, and almost always exclusively in the context of proper names, such as in company names, in an artistic collaboration, or perhaps an academic reference. Marks & Spencer. Emerson, Lake & Palmer. Ant & Dec. You get the idea.
To me, it implies a slightly stronger, more committed union than might an ordinary ‘and’ so you shouldn’t use it to join two names unless you are sure that the ‘marriage’ is official and the ampersand has been adopted by the parties involved.
When not to use it:
a/ in any standard sentence with an ‘and’ used as a conjunction;
b/ within a list (eg red, yellow, blue & green);
c/ in a pair (salt & vinegar);
d/ &c – meaning etc.;
e/ (Chief Pet Hate) as a substitute for any occurrence of an ‘and’ string in a word – such as s&castle, st&ndoff or, indeed, ampers&.
There are more crimes but my head would erupt in an Eyjafjallajökullian manner were I to continue.
I guess there’s one exception. And that is when you have a long list of items, one or more of which are, for want of a much better word, ‘anded’. So I might let this one pass, although I’m still not overly keen:
We ate sandwiches, bubble & squeak, prawn salad, fish & chips, cake and ice cream.
Here, I guess the ampersands additionally tell you that that you’ve not reached the end of the list yet while the ‘and’ tells you you’re about to. But I’m still fuming subtly from a side vent…
Ought I dehuff a bit, do you think?