This isn’t something I’ve ever really wondered. For a native English speaker, which one to use is rarely in doubt. Sure some regional dialects might use is and are in non-standard ways, but if asked, most speakers of these dialects would know the “proper” form of the verb to be to use.
Which is why I was surprised to see the following headline on the BBC website:
Is England and Wales experiencing a crime wave?
Surely, I said, that should be, Are England and Wales experiencing a crime wave! Even though they’re both part of the United Kingdom, and of Great Britain, England and Wales are still separate countries. If you’re referring to them as distinct entities, then it’s a plural sentence, and you have to use are!
But also, no.
While they are separate countries, and that headline certainly looks like a sentence with two nouns, England and Wales actually form a single legal jurisdiction. England and Wales in this sense is a constitutional successor to the Kingdom of England, which existed until 1707, when it united with Scotland to form the Kingdom of Great Britain.
The continuance of Scots law was guaranteed in the union with the Kingdom of England, so Wales and England remained under English law, separate from Scotland.
This is why, if you watch the news on British TV, you’ll often hear about, for example, crime statistics in England and Wales, but not Scotland or Northern Ireland. Or figures will be presented for the constituent parts of the UK, except with England and Wales lumped together.
So in this sense, the headline was correct, as it was referring to a single legal jurisdiction. Still, it sounds weird, because it sounds like we’re talking about two different things. Despite how seemingly obvious it is when to use is or are, there are little oddities like this which muddy the water.
There are a lot of people here.
There’s a lot of people here.
I think most people would say that the first sentence is grammatically correct, because we’re talking about people, which is plural. And I myself would usually use there are in a case like this.
But, there’s a case to be made for there is, because it directly refers to a lot, which is singular. There
are is a logic to that, but still, I think insisting on using there is in this case would be pedantic. When we talk about a lot of people, we’re thinking about many different people, not a singular mass comprised of people. We’re thinking in plural terms, so we use are.
But if you really want to use is, that’s OK, and if you’re referring to the legal jurisdiction of England and Wales, then you can rest assured that you’re grammatically correct!