Is cavity wall accessible from roof space?

[Happyunited]

I was wanting to drop a tv aerial cable down my cavity to the bedroom below. I haven't had a good look because the roof slopes down where I want to drop the cable but my question is should I expect the cavity to be open for me to just drop the cable down? or will it be capped with bricks?

Thanks in advance for your answer.

 

[noseall]

some are closed and some are not.

these days, we tend to allow the cavity insulation to carry on up to meet the roof insulation - hence, ours are open but full.

some earlier cavities particularly those that were deliberately left empty would be closed off at the top with header bricks.

bu99erd all round really.