Crack along wall next to door frame

[Funkadelic]

I have an issue with the plaster next to my door frame, over time it has developed a crack from the floor up due to the door shutting. At the floor a section of the plaster has broken and created a crack that bevels out.

What are my best options to rectify this issue, I know if I plaster straight over the crack it is likely to weaken over time and re-appear. the plaster board around the area of the damage near the floor appears to be loose against the wall too.

I have attached some images and appreciate any advice.

 

[martin hill]

Looks like a classic case of the door lining/frame not secured enough into the brick work. Got a 1900's terrace myself and the door linings were fixed by a big wooden block instead of a brick. Or in some houses later on a wood wedge was used instead of mortar bed and the frame nailed to that. Over time with banging shut the mortar has crumbled loosing the frame. Take the plaster off close to the door frame up the wall and have a look how it fixed in place.