Cracks on internal walls. Advice please

[kizkiz]

Hopefully the pics are attached.
We went to see a house yesterday that had quite a few internal cracks. Most were hairline, but the top floor had cracks almost all the way around where the walls meet the ceiling.
There are no obvious cracks on the outside brickwork anywhere that I could see
The house is a 3 storey townhouse. Built 60s/70s. Has been a long term rental, so not decorated in many years.
I know it's impossible to be sure, but from the pics, is it likely to be a major issue, or just a paint/plaster problem?

Really appreciate any insight.

They look like shrinking plaster to me. You often get them following the outlines of the plasterboard behind.

Yes or using something like painters mate which gives a lovely smooth edge to start with but then shrinks & cracks like that. It wouldn't particularly worry me from those pics.

Thankyou both.
The other half showed a friend at work who is a plasterer, and he said the same.
It had better be ok, as our offer was accepted!