This week, two of the world’s biggest tech companies have found themselves in PR crises of their own making. Why did Apple's new iPad Pro 'crush' advert misfire so badly? Meanwhile at Baidu - China’s biggest search engine - its PR boss has lost her job after videos of her promoting a toxic work culture went viral. David Yelland and Simon Lewis go to the heart of a secret and little understood reputational war and look at the real battle between the west coast of America and China’s Silicon Valley. And - bowing out gracefully. How Nadhim Zahawi’s exit strategy from politics ticked all the PR boxes. Producer: Eve Streeter Editor: Sarah Teasdale Executive Producer: William Miller Music by Eclectic Sounds A Raconteur production for BBC Radio 4