Probably simple job.

[PriestyUK]

Don't you just hate it when you go to a job because they have a leak, and it turns out to be a compression joint/nut in the wall that's leaking like the one above arhhhhhhhhhhhhhh why O why

 

[Ric2013]

The reason the tape is wrong is that you are trying to seal a thread on a fitting on which the seal should already be estalished before the thread. In other words, if the water is getting to the thread, you already have a leak. It does indeed look like a tap connector, so goodness knows why it was sold to you.

The pipe at an angle certainly doesn't make your life easy.

Leaving that aside for now, I'm with Simon F on this one...