TAIPEI, Dec 11 (Reuters) - Taiwan's defence ministry reported a spike in Chinese military activity around the island on Wednesday, including 53 military aircraft, with Taiwan on high alert over Beijing's latest pressure campaign. China's military has yet to comment and has not confirmed it is carrying out any military exercises. China, which views democratically governed Taiwan as its own territory, had been expected to launch drills to express its anger at President Lai Ching-te's tour of the...