Cavity filled around air brick, - advice please!

[SouthDrive]

Hiya, I was doing some work in my kitchen and behind a cabinet was the air brick below.
(small semi detached cavity wall house from 40s/50s)

Q1) in the pic below, the cavity surrounding the air brick appears to have been intentionally closed on all sides - forming a sort of air tunnel into the kitchen -
I assume this was done to ventilate the room?

This property used to have a gas fire and back boiler downstairs.

Q2) this air tunnel is, I assume, creating a good bridge between inner and outer skins, increasing moisture in the inner skin etc...

Should I get rid of tunnel, separating the inner and outer skins of brick work? (My gut feeling is yes, I was wondering if I had overlooked something)

Q3) is it normal for the cavity to be full of rubble?

Thanks
Will

 

[jj4091]

Yes
Yes
Yes

 

[SouthDrive]

Thanks

 

[^woody^]

Yes
No
Sometimes

 

[SouthDrive]

Hiya, could you elaborate on Q2, you said no, could you explain why,

Yes
No
Sometimes

Thanks