operationally to disrupt Chinese activity of national security concern in the past week. Addressing a row over the collapse of a case involving alleged spying on behalf of China in the UK, Sir Ken said the alleged activity was disrupted by MI5 and that it was "frustrating when prosecutions fall through". The government and the Crown Prosecution Service (CPS) are facing questions over the collapse of the case. The CPS dropped the case last month after deciding the evidence did not show China was a threat to national security. But witness statements from the UK's deputy national security adviser Matthew Collins - published late on Wednesday - are clear that the Chinese are carrying out spying operations against the UK, raising questions for the government and the CPS about why the prosecutions did not go ahead.  In the documents, he said China was carrying out "large scale espionage" against the UK and was "the biggest state-based threat to the country's economic security". Sir Ken described Mr Collins as a "man of high integrity and a professional of considerable quality". (BBC)