Hundreds of spectators were swept off their feet when the world’s largest tidal bore surged up a river creating an exceptionally powerful wave.

The victims were standing on the banks of the Qiantang River in China’s Zhejiang province yesterday when the surge took them by surprise.

The power of the river was exacerbated by Typhoon Trami, a devastating tropical storm which has swept across the region this week.

Bystanders were supposedly protected by barriers lining the banks of the Qiantang at the time of the surge.

As well as knocking over spectators, the wave dragged off vehicles and flooded a water-treatment plant.

The river had reached a height of 6.6m, with the surge adding an additional 1.3m.

The tidal bore in the Qiantang, which sees large waves created by the incoming tides from the East China Sea, is believed to be the biggest in the world and is the site of an annual Tide-Watching Festival.

It has been significantly worsened this week by the arrival of Typhoon Trami, which made landfall in Fujian province early yesterday morning.

The storm has brought heavy rain to the region, which has already been hit by flooding in the wake of Typhoon Utor.

Around 250 people were left dead or missing by the floods over the past week.

Trami wreaked havoc in the Philippine capital of Manila and in outlying regions, killing 18 people and leaving four others missing, but caused only minor damage when it passed over Taiwan.