UK Is this asbestos?

[bartkusal]

Hi everyone

Just wonder is anyone seen these before? Bit afraid, as it may be asbestos. Maybe someone know for sure.
It's AB British Standard written on the front.
Came to install electrical fireplace and found this beauty after cutting the opening through plasterboard.
Any thoughts?
Thanks

 

[snowhead]

That's fire brick.

When there was a fireplcae in front of it, there may have been asbestos rope filling the gap between the 2
But the front of the fire back has been cut down to allow the plasterboard to fit flush.

similar to this;

Pardon our interruption...

 

[buzzlightyear]

Wow that a big hole for a knock out box
Me thinks you have gone over board. Lol

 

[Soi disant]

Wow that a big hole for a knock out box
Me thinks you have gone over board. Lol

 

[buzzlightyear]

He will need bigger then that, could it be stretched. Lol.