Sink fitting pipe question

[DannyC]

Hi all,
Been trying to fit new sink and move from pillar taps to a mixer. Previous piping was all rigid pvc with push fittings (not sure if I'm getting the lingo right). Went to toolstation to buy flexi-hoses to connect the new tap and the pipes and they sold me ones with an apparent push fit connector (see below). Problem is it is leaking badly when we turn on the water! The other fittings work by pushing in and then twisting to give some compression (I'm guessing) but the connectors on the flexible hoses don't have anything to twist I don't think. So i've just pushed the pipe in but it isn't giving a tight seal. Any ideas? Have I got the wrong hose or doing something stupid?

 

[JKG]

Is there a insert in the plastic pipe and is the pipe fully into the fitting

 

[SimonG]

Doesn't look square on the pipe. As above, insert and pushed fully home.

Not as easy as it looks this plastic plumbing 😉