LONDON, Jan. 22 (Xinhua) -- Work on Britain's biggest flood defense project since the building of the River Thames barrier began on Monday.

Environment Minister Therese Coffey marked the start of works on the Boston Barrier flood defense, breaking ground on an Environment Agency scheme that will protect 14,000 homes and businesses from tidal flooding in Lincolnshire county.

Coffey said: "This will make sure Boston is one of the best protected towns on the east coast and I am proud to be putting the first spade in the ground on this project. It is expected that works will be complete by the end of 2020, and will make Boston one of the best-protected areas from tidal flooding outside of London."

The scheme will feature a movable gate across the River Witham, new flood defense walls on both banks, and a replacement gate across the entrance to the existing Port of Boston.

The barrier's 25-meter wide hydraulic-powered gate will be raised when flooding is expected, preventing high tides on the North Sea from raising river levels.

Boston has a long history of tidal flooding, most recently in December 2013 when hundreds of homes were flooded. Flooding also occurred in 1953 and 1978.

The Environment Agency is investing more than 3.6 billion U.S. dollars in more than 1,500 flood defenses to protect homes and businesses across Britain by 2021.