Covering over old wall vent

[emoose]

About to start work on the downstairs box room and I want to know if I can safely block up this ugly vent and fill the void behind.

Looking down the street a lot of my neighbors have done away with it.
I've blocked it up with newspapers the last few weeks and no condensation/mold has appeared.

Its a 1930's chalet style house.

What do people think?

(apologies if this is in the wrong section)

 

[noseall]

I've blocked it up with newspapers the last few weeks and no condensation/mold has appeared.

Condensation related mould will start to appear in some obscure places like behind sofas, wardrobes, sideboards, cupboards and usually on an external North or East facing wall.

If nowt has appeared in the recent cold weather then you are not likely to suffer from bricking up an already blocked air vent.