Shanghai's financial markets are in freefall - down more than 7.6% on Tuesday, and more than 40% since June. It’s contagious, with a black Monday for global stocks and a steep thud for commodity prices. There are also clear signs that the slowdown in growth is bigger than stated – but by how much? China's handling of the crisis was meant to reassure investors, but instead has shown up the shortcomings of Beijing's brand of state-run capitalism.