A spokesperson for the Home Office commented:"The home secretary was not consulted over the decision to grant Mr Ai a one month visa. She has reviewed the case and now instructed Home Office officials to issue a full six-month visa. We have written to Mr Ai apologizing for the inconvenience caused."

It was reported that the refusal came from Weiwei not declaring he had a criminal conviction on his application for a visa. In 2011, Weiwei was arrested and imprisoned by the Chinese government for 81 days, but did not face a conviction.

The artist will travel to the UK in September for the opening of his solo show at the Royal Academy.