When does Junkyard Wars return?

Scrapheap Challenge was a British television show where teams of contestants build a working machine that can perform a specific task, using materials available in a scrapyard. The programme ran for eleven series and was originally shown on Channel 4. The format was exported to the United States, where it was known as Junkyard Wars. The American show was also produced by RDF Media, and was shown on The Learning Channel.