• Bank and finance shares collapse by as much as 30%• Market falls more than 23% as bourse reopens after five-week shutdown•China woes deepen on manufacturing slowdown 8.40am BST The market has opened and it’s not pretty. The Athex Composite has plunged more than 20%, to 615.12. The falls are even deeper in financials, with banking shares down by as much as 30% – the maximum allowed.