Go ahead but get ready for more lateral growth in the future. After cutting pinch the cut end to keep drops of sap from falling on your floor or carpet.

Hard to tell from the picture, but it might be Schefflera arboricola - it responds well to cutting back, though to be fair, it responds better if it's cut back in spring. Still, you can't put up with that trailing in the way it is (I've never seen one do this, they usually grow upright, or mine do anyway, perhaps it has suffered low light conditions?). If you like, cut off everything you don't want, then take off the tops of what you've cut off, about 8 inches long, strip off the lower leaves and pop them in a bottle of water on a windowsill - if this is done in spring or early summer, roots are formed within six weeks, but you might find it takes longer at this time of year. Keep the bottle topped up as the water level drops over time. That way, you can make a new plant for yourself if the other one doesn't do too well after hacking it back....

thanks
it has grown sideways as it hit the ceiling
over 12 yrs ago ! if it was verical it woul
be about 14ft high!
trying to find a home for it
and do not want to propergate any more!!
seems a shame to bin it

Well just cut it back to about a foot then, above a leaf node - if you gave it to me, that's what I'd do anyway....