Floating horse hospitals, troops billeted in empty lock chambers and heroic tug boat owners are all showcased in a new exhibition about canals during the First World War.

Waterways on the Western Front opened at the London Canal Museum, in New Wharf Road, King’s Cross, today and follows the untold story of these vital wartime lifelines that saved millions from starvation.

Previously unseen film and photos from the Great War show the enormous contribution made by canals to the war effort.

They carried tens of thousands of wounded - both human and equine - for hospital treatment and transported five million tons of food to Belgium – people had to drink drank canal water to prevent them dying of thirst.

A secret town was even built in Kent to transport thousands of tons of munitions every day to the front line.

The exhibition also highlights the story of Henrick Geeraert, a tug boat owner who almost single-handedly stopped the channel ports falling into German hands.

With the enemy fast approaching, the man who was meant to open the canal flood gates to stop their advance had run away.

A soldier remembered having a drink with a boatman, Mr Geeraert, who claimed to know how to operate the sluice gates.

After a desperate manhunt he was found, then taken into no-mans land to let the water out and flood the German positions.

Charlie Forman, project manager of the exhibition, said: “When we started investigating we didn’t realise how important canals were during the First World War - there was no record and this is the first time all the information has been gathered in one place.

“The scale is just extraordinary - there were 500 barges used to transport food to feed the population on Belgium and stop them starving.

“It was thanks the Herbert Hoover [later US president] that a deal was brokered that both the British and Germans would tolerate.

“The British were worried the German solders would eat the food, while the Germans weren’t too happy about this food arriving that they couldn’t use.

“And a whole town of 19,000 people sprung up between Ramsgate and Sandwich, with a mile of wharf to load munitions onto ocean-going tug boats.

“It was top secret, and we don’t think the secret was ever discovered because the Germans never bombed it, despite bombing other places nearby.

“All that remains today is a few bits of wood sticking out of the ground.

“And the story of Mr Geeaert is incredible - he really saved the day.

“Without him it is almost certain the Germans would have taken Calais and Dunkirk.”

Waterways on the Western Front runs 12 April 2015 at the London Canal Museum, on Tuesdays to Sundays from 10am to 4.30pm.

Admission is £4 for adults, £3 concessions and £2 for children, but free on the first Thursday of the month between 4.30 and 7pm.

For more information,visit www.canalmuseum.org.uk.