I've been out checking names of OSM roads. ITO World's OS Locator tiles help to find the places where OS Locator and OSM don't agree. Often on rural roads the names are missing from OSM because there is no name board, but sometimes there are name boards and the difference is because OS Locator does not agree with the name board.
Normally I don't look at Google maps - I'm not interested. Their marking scheme clearly is different from OSM because farm tracks show up as roads for example. When I did look at a Google map page that someone linked to I noticed that an OS Locator name that is wrong on the ground appeared in Google maps. Recently I've checked a few more and whenever OS Locator disagrees with my findings on the ground, so does Google maps. In a couple of occasions OS Locator disagrees with OS StreetView and Google matches OS Locator. I have also used Google's StreetView to look at the name plates where they exist and sure enough the name plate disagrees with the road name on Google's page. Google have the photographs to show the real, on-the-ground names in the StreetView system, but they haven't used them.
Some people might say that the OS names are correct and the name boards might have errors, but I strongly disagree. When the council replaced some damaged name boards locally and one was wrongly spelled, there was a fuss from the people who's road name had apparently changed. They insisted the council put it right, and the council did replace it, though it took nearly three months. My point is that if a name is wrong on the ground people will have it corrected, but if the name is wrong in an OS database no one complains so it doesn't get corrected.
When it comes to Google's naming of roads, the only conclusion I can come to is that somewhere in the supply chain of data that Google uses, OS Locator or some similar OS data is used. Google, or one of their suppliers may have an agreement with Ordnance Survey, but if they are using the open data I wonder why they don't attribute OS?
By the way, why did OS choose "StreetView" as the name of one of their hurriedly-put-together OpenData when Google already used the name for a quite different product?