Sky News visits the front line as China imposes itself on areas of the South China Sea claimed by five other countries.

Technically, we are in international waters, but we are heading close to the Chinese-controlled Subi Reef, and the Philippines fishermen on board are frightened.

The captain and his crew are up on deck keeping watch, anxiously scanning the horizon.

Some of the men want to turn around. They are afraid of being intercepted, and rammed.

Tensions in the region are high – and rising.

China lays claim to most of this sea as its sovereign territory, but that is disputed by five other rival claimants.

http://news.sky.com/story/1700915/exclusive-unseen-battle-for-south-china-sea