IT was the most terrible day in the history of the British Army with more than 57,000 casualties, of whom nearly 20,000 were killed.

But the first day of the Battle of the Somme – July 1, 1916 – was just the beginning of a four-month operation that would end with more than 1.5 million casualties.

The shattered fields of northern France ran red with blood and, to this day, the countries that took part remember the events with abject horror.

Now, photographs of that first day have been made available in an online exhibition by the Green Howards regimental museum, in Richmond, North Yorkshire.

The photos were taken, unofficially, by Bridlington-born Lieutenant John Stanley Purvis – who was risking a court martial by doing so.

He and his men, of the 5th (T) Battalion The Yorkshire Regiment (Green Howards), were in the second line of trenches and watched as the first wave of soldiers went over the top.

One of his photos shows the advance of men in the forward trenches, another is a general view of the battlefield and a third the moment a shell explodes nearby.

Another is an image of two men in the trench with their rifles ready, at the entrance to a tunnel under No Man’s Land.

Lt Purvis was one of the lucky ones. He survived the war, taught classics after a Cambridge education and was then ordained. He served as a vicar in York and Old Malton among other places.

Eventually, he became a Canon of York Minster and played a major role in the founding of the city’s Borthwick Institute of Historical Research, now part of York University. He died in 1968.

His pictures have now joined hundreds of others on the Green Howards Museum’s website as part of a Lotteryfunded project to scan and upload as many images as possible.

Museum director Lynda Powell said: “It is amazing that a young lieutenant on the Front, in 1916, had both the desire and the camera to take pictures at a time when his life must have been in imminent danger.”

The collection can be found at greenhowards.org.uk and follow a link to the museum.