Tacklebox UK just published their latest line test report. Should make for some interesting reading.
Snippet from Tacklebox.co.uk
Almost every line commonly used for carp fishing ...
has an under-rated breaking strain indicated on the spool or box. With a good knot, most lines will always break at a higher strain.
With no international guidelines for indicating breaking strain or diameter, manufacturers under-rate lines to different degrees. A line labelled 12lb by one company may consistently break around 20lb; a line labelled 12lb by a different company may regularly break at just 14lb.
To give a better idea of the specifications of lines we sell, we have tested breaking strains and diameters ourselves.
Visit the link below for more details.