Sealing up gas coming into house

[marsaday]

Can this opening be sealed from the inside, so stopping the draught coming into the hallway? Or does it need this airflow. I understand it needs to be vented from the outside, so definitely do not seal this side.

The pipe is sleeved and is bringing in a big draught into the hallway.

ps. posted this in central heating, but no replies, so maybe it needs to be here.

 

[PuraTherm]

Yes it must be sealed from the inside. Was this recently installed?

 

[metaldust9]

no ,if its going into the meter cuboard it must be sealed on the meter side /outside with a special putty forgot the name of it but it stays soft only sealed on inside if thro a cavity to outside with sleeve

 

[marsaday]

no its not a recent instal. house 100yrs old so gas in since 60's probably.

the wall is not cavity (solid). i will seal up. thanks