- IT IS little more than a week since Ai Weiwei, a Chinese artist and perpetual irritant to his country’s authorities, was given back his passport, marking the end of a four-year travel ban. Mr Ai has already made arrangements to visit Europe, stopping first in Germany. But on July 30th it emerged that the visa for his proposed onward trip to Britain would be unexpectedly limited, after Mr Ai received a letter from a bureaucrat saying that his travel would be restricted because of a failure to own up to his “criminal” past. Mr Ai is used to such interference. The surprise was that the letter came not from the Chinese authorities, but from the British.Rather than be given the six-month visa for which he applied, Mr Ai has been given permission to be in Britain only between September 9th and 29th. That means he will be safely out of the way by October, when London is expecting another Chinese visitor: Xi Jinping, the president.