How to fill large crack in brick work

Hi, I want to know how i can fill the gap in pictures, would it be cement or a sand and cement mix, if so what ratio? Thanks

This is the back garden wall, it's basically the back of my shed though the other 3 walls are not attached, i believe it was caused by plants forcing through, i have cut them back and just want a solution to repair the best way possible, i don't want to have it rebuilt as the wall seems solid aside from this large crack.

Thanks

I'm not sure if the pic worked or not? I linked to google drive but not sure how that works fully if it's not visible, I'll try again here

https://drive.google.com/file/d/1bg07IpJRfHGeJzDw2tRyehB2YYbmMgdZ/view?usp=sharing

Grantyy, good evening.

Is there a tree nearby? or was it simply years of large bushes or such.

How much earth is this wall retaining[if any?]

And is each side of the crack in the wall still in line with each other?

Ken.

Hi Ken, thanks for your help!

There is no tree but there is a large rose bush in my garden in front of the shed and growing over the top of it, there were also bramble type weeds at one point but they have been cleared, the other side is the end of an alleyway and often used as a dumping ground but us that live that end clear it every so often.
There is no earth retained by the wall
The wall is in line with each other

The crack looks to be lifting from below, or sinking on one side of the crack. Filling is easy enough but it won't fix the underlying problem. 1:1 cement to sand is concrete. 1:3 cement to sand is the mortar between the bricks. So, it depends on how durable you want the filler to be. Whatever you choose, it will not prevent the crack expanding.

Clean the crack out and fill with semi-dry 3:1 S&C.
The semi-dry mix will last for ? and then you will have to do it again.
Do not use concrete.

1:1 cement to sand is not concrete.

Grantyy, good evening, again.

Looks as if the left has area of wall has dropped [about???] 20 / 25.mm ?? if you look at the relavent levels of the bricks and paint line??

Do you own the wall on the other side of the breeze block wall on the left of the image??

If you can access the other side of this wall, what i would consider is to install 4 X 1.m long "Helifix" bars roughly equally spaced over the total height of the wall, as noted, install these bars on the other side of the wall because??? there will be a different colour of mortar pointing where these bars are installed, then fill with mortar as mentioned above.

If you do not own the wall to the left behind the breeze block wall your neighbour will need to consent to any work???

As for "Helifix" suggest you Google and have a look at "crack stitch systems" they are used extensively in the repair of Subsidence damage.

Ken.