Nuts.

And it gets even worse ...

"NEARLY 2,000 bolts which help hold up the Forth Road Bridge may have to be replaced after several were found to have cracked nuts. Laboratory tests are being carried out to determine the cause of the problem, which is believed to be a world first on a suspension bridge."

The fact that the problem is a "world first" is probably not unrelated to the fact the Forth Bridge is the only one run by FETA.