http://www.wired.co.uk/news/archive/2014-07/31/nasa-validates-impossible-space-drive
Britain invented this contentious item. It has been tested in China and now by NASA in the US. Guess what? Despite originally posting this I'm still not convinced. To be honest it is very difficult to see how this can avoid smashing into the conservation of momentum law and coming off worst.
Then again, nature has never cared about what scientists think, it just does it's stuff.
If it does truly work it could revolutionize space travel, So I guess I'm pessimistically optimistic ;D