Is there a flexible filler for a crack in internal wall which opens and closes every Autumn?

[Lifebee]

We live in London and a combination of the clay soil and a huge tree in the street outside our house cause a few cracks at the front of the house to open up every Autumn for a month or two before pretty much closing again.
They only open to 2/3 mm but it's annoying as they are in quite a visible place.
Is there a filler you would recommend which expands and contracts but yet can be sanded for painting? Does such a filler exist?
Thanks.

Anyone?

Last chance!

Sorry don't think there is! If the tree outside is very large it may be causing damage to your property so the council should investigate.

You could try caulk, it's like a flexible filler. It can't be sanded, but you smooth it in place when you apply it to give a level surface. www.screwfix.com/c/sealants-adhesives/decorators-caulk/cat850098