Cracks in bricks

[Olliewc]

Hi all
The main side wall to my house has a lot of cracks showing in brickwork. Generally vertical hairline cracks in individual bricks around 1 mm wide throughout the wall but generally lower down. No particular pattern and no cracks in mortar. The house is a victorian semi. The wall appears to have been repointed at some time before that. I've been in the house 5 hrs and there is no obvious deterioration in cracks, as far as I can tell.
Any ideas as to cause, serious or not? I suspect the pointing may not suit the old wall but this is just a guess.
Any help is appreciated
Cheers

 

[terryplumb]

Frost damage probably.

 

[^woody^]

They were like that when made or laid. Not a problem.

 

[Olliewc]

Thanks guys that's reassuring. Suppose I had better get them filled before long though.

 

[tony1851]

The cracks don't extend across the mortar, so not a problem.
Why attempt to fill them? It will end up looking a mess.