Drainage pipe in basement overflowing. Help!

[BlackCoffeeAndToast]

I'm embarrassed to admit I've lived in my house for almost 7 years and only today noticed drainage point in my concrete basement floor because it is suddenly overflowing and creating a puddle. It's the end of a pipe leading I don't know where! I've cleaned up the water this morning and it isn't overflowing or refilling by tonight, so I'm assuming it's something to do with the constant rain we've been having lately and drainage issues further along the pipe system, but I really don't know what my next steps need to be. (It's definitely clean water, so I'm assuming it's drainage from rain)

It does, however, clarify why I can never get on top of the damp issues down there...

I had exactly this last winter. Can you post a photo?

There's water not draining away at the bottom of the pipe.

is there a pump in your basement (sump pump) to drain away water? It looks like that square space was a sump pit that has been partially covered.

It's possible, but I don't know.

The basement used to have access via a door and steps to street level, as well as a window along the stairwell and a coal chute. We now have a small window where the door once was, and a drain outside the window that I can't get to, there's a welded grate above it.

I feel like I need to take a look at that grate again and investigate the status of the drainage point.

How old is the house?

Is the basement original or has it been altered?

The thing in your pic looks like it might be rigid hard plastic in a terracotta colour, 100mm diameter, typical for modern underground drainage. Though it might have been connected to an older drain. Is that right?

It might be a trap or gulley. Probe it and see if there is an outlet in one side, probably near the water level, or if it goes down and then bends towards the horizontal.

Thers seems to be another pipe behind it. Is that also 100mm diameter? Where does it come from? Is there a kitchen or bathroom above?

Look outside. There will be a manhole nearby.

Thanks @PigletJohn

It's edwardian, the basement is original as far as I can tell, there's a fireplace down there that connects to the one in the room directly above. The only window in the basement is where the door was, I believe.

I've attached a picture of the outside, there's a grate in front of the window that's cemented in place, there is a fair amount of mud and detritus under that grate, which is very low down, and I've just used a fully extended painting pole to dig through it, the drain is completely covered. As you can see, one of the gutters drains into this point as well.

The pipe indoors does seem to have an outlet, but nothing is draining below the opening.

I'm going to have to hack into the cemented grate and clear the drain, aren't I?

Yes

But I would expect that type to lift out of an iron frame that is concreted in.

Does the window open?