Wed 10 Oct 2006Tension high in the limbo that is Castro's Cuba Letter from Havana: Tensions are running high in the Cuban capital. The city is crawling with police. Paired officers stand guard on every block in the tourist quarter of Havana Vieja. Their radios crackle while the black batons dangling from their belt holsters gleam in the midday sun.But, away from the holidaymaker bubble where the police are little more than security guards who keep would- be beggars away from western tourists, the real action is taking place.