It's the ignition switch just like ivanidea linked. Mine actually went bad during my last MOT so I got a fail on wipers and indicators. I got there just after he'd had to close the job to get the next one started. I turned the ignition off and on again and everything worked again so I got the pass after a short wait.
I forget where I got mine from. I'd try Rockauto and ebay. Pic below is my old switch. The worst worn contact is the one that caused the problem. As you can see it isn't the only contact going bad, so tapping one circuit to feed the wiper/indicator/radio feed might just be adding to problems down the line.
