By now, if you are a US fan of UK soaps you should have heard about Britbox. Below I write about what they have and don't these days.
When I heard about Britbox I was excited, because it meant that some programs not available to the US audience may finally be easy to view. That said, while I appreciate the ease, there are some disadvantages. The main one being that depending on what you are interested in, you may not find what you are looking to see. My biggest issue is the amount of time one has to watch and the fact that if you don't know the series you are dumped into the middle of the action. I don't get why they don't have archived or older episodes so you could learn more about what you are viewing. That would be a very important thing to entice me to spend money to watch.
As of now, they have three shows available. "Eastenders", "Emmerdale", and "Coronation Street", so three out of the four UK early evening soaps can been seen on this service.
Eastenders - they have episodes from May and June 2017. So it looks like they keep up two months and then delete.
Emmerdale - they have episodes from May and June 2017. So it looks like they keep up two months and then delete.
Coronation Street - they have episodes only from the current week. If you are a Corrie fan, and you know you won't get through them quickly, you do have a legal alternative. Hulu has picked the show back up again. They have all of 2016, and 2017, but tend to be three weeks behind the UK airings.
If you are a fan of "Upstairs Downstairs" and want to see what that soap was like, which aired on PBS in the US in the 70s that is also available along with other UK dramas. Many have performers that are known for other programs or movies.