Is the fireplace lintel arch likely to be strong enough?

[Hazzle]

Hi

I've knocked through my chimney breast. I've found the arch, which is acting as the lintel. I'm wondering if it's likely to be strong enough to hold the chimney stack as is, or if I should get someone in the check and support it ASAP.

Any advice would gratefully recieved!

Thanks
Harriet

 

[^woody^]

The arch will stay up

 

[Hazzle]

Thank you!