Oh my God!
Had a Leak. Bought a new cold tube from Homebase. Thought that would fix. Now two days, leak at one end then the other.
What other industry or walk of life would a product not work. We had Concorde, we have mobile phones, but to connect water pipes we have a large thread and a bit of rubber!
Reading up on what I studies at College as Polytetrafluoroethylene
PTFE, people say they use this as it has low friction to get nuts on further. I think by association it also acts to fill the voids in the threads and hold back the water.
Cannot believe that some improved method has not been invented, where the presence of water pressure actually increases the lack of egress.
Good luck all.