Robertson was also travelling to Rome. Both he and General Douglas Haig deplored Lloyd George’s attempts to find a way around the Western Front. They were convinced he was toying with public dismay at the scale of killing in Flanders, only pretending not to understand why the enemy must be attacked frontally where he was strongest. At various times, after all, he had promoted the Balkans, the Eastern Front and the Middle East as alternative theaters. Now he was doing the same with Italy, and Robertson would have none of it. He neither trusted the Italian estimates of their own potential nor believed that Germany would let Austria-Hungary reach a separate peace, regardless of how well the reinforced Italians might perform.

In this situation, Lloyd George might have been expected to exercise his powers of persuasion on the French prime minister, Aristide Briand, and his minister of war during their hours on the train. He did nothing of the sort. He did not even show them his memorandum outlining Entente options for 1917. When the party reached Rome, he sent the cabinet secretary to brief Cadorna. But the canny Robertson got to him first.

When Lloyd George made his case, the British and French generals’ skepticism was deepened by the overdone praise of Cadorna. The French objected that lending batteries to Italy would jeopardise the Nivelle offensive, so Lloyd George promised that the 300 guns would ‘absolutely’ be returned in good time. When Cadorna’s turn came to speak, he showed no enthusiasm. Guns that had to be returned in May were, he said, not worth having. An onlooker who knew him quite well was Sir Rennell Rodd, Britain’s ambassador to Rome. Watching Cadorna pass up a unique chance of substantial Entente support, Rodd reflected that it was a moment when character shapes outcome.

Lloyd George offered to let Cadorna keep the British guns for longer. This off-the-cuff contradiction of policy infuriated Robertson without reassuring Cadorna, who was haunted by the specter of a second Austrian attack out of the Trentino, dismayed that the Entente would lend no troops, and troubled that he would have to attack, inviting German reprisals, without simultaneous offensives on other fronts. Lloyd George did not forgive Cadorna for squandering ‘the most promising chance afforded to him to win a great triumph for his country’.

On their arrival, the British troops found the Italian soldier an enigma: ‘Of all armies I should say that it is most difficult to gauge the standard of the Italians. One is constantly confronted with surprises. The Italian is capable of doing everything, and is a master at doing nothing. As regards physique he is, I think, unsurpassed though of low stature, his strength is remarkable. He can carry more than a British or French soldier. Infantry may be seen straggling along a road, the reverse of our idea of ‘smart’, but he will walk all day and feed on little. He is practically never drunk and, though illiterate, extremely handy and ingenious. He has no idea of punctuality or time. 8 o’clock may mean 8.30 or 9.00. But when he works, he works extremely well. The morale of the Italian is easily affected. As an Italian officer said to me, “Tell him he is a brave man, and he becomes one!” Hence the regiments with good traditions are excellent, those without traditions or with bad reputations are very bad, and the contrast is stronger than in other armies.’ (Lieutenant Colonel Charles Buzzard, Headquarters, 144th Heavy Artillery Group, Royal Artillery)

As the army prepared for another winter, visitors noticed a sullen weariness at the front. A reduction in rations in December did nothing for the soldiers’ spirits. The new year brought several worrying incidents where new recruits protested at the draft. Infantry shouted abuse at passing staff cars. When a journalist mentioned these omens to Cadorna, he waved them away. ‘It is like that everywhere, and of course the soldiers are tired after two years.’ A few serious cases of insubordination had been handled in the only proper way: by shooting the malefactors, ‘to prevent sparks from becoming fires’.

The Tenth Battle has to be understood in terms of ridges and summits. Mount San Gabriele, east of Gorizia, stands as an isolated summit. Monte Santo, further north, is the southern tip – and highest point – of a ridge that runs southeast for six or seven kilometers from Hill 383, above the Italian bridgehead at Plava. On its three other sides, Monte Santo falls away steeply. Italian shelling had reduced the church and monastery on its summit to ruins.

Five regiments were launched against the lone Habsburg battalion on Hill 383. Outnumbered by 15 to 1, the Austrians still inflicted 50 percent casualties on the attackers before succumbing. Italian interdiction fire played a part: reinforcements could not reach the beleaguered defenders.

On Monte Santo, after a devastating bombardment involving the batteries hidden in the summit of Sabotino, the Austrians could not resist the Campobasso Brigade. The summit was taken but could not be held. For the next 24 hours, attackers and counterattackers chased each other across the summit in increasingly ragged waves.

On the central Carso, the Duke of Aosta threw 60 battalions at the fortified line beyond the Vallone, aiming to deepen the salient that was carved out during the Ninth Battle. The Duke had dramatically increased the reserves, ready to exploit any success. But there was nothing to exploit. To their amazement, the Italians found they were outgunned on the central Carso. With their usual pinpoint accuracy, the Austrian batteries barred the way.

Batteries belatedly opened the second phase of the battle. Supported from the air and by floating batteries at the mouth of the Isonzo, the infantry’s surprise attacks widened the salient, rolling over three Austrian lines to capture a band of territory two kilometers deep from central Carso to the sea. The Austrians melted away in front of the Italian right. Habsburg prisoners reported a crisis of morale, yet the Austrians did not buckle.

The Austrians would, though, have the last word. General Svetozar Boroević used his reinforcements from the Eastern Front to launch surprise attacks north of Hermada, regaining some of the ground lost to the Italians.

Cadorna’s first assault in the area, in November 1916, had come to nothing. Now he resolved to overwhelm the Austrians with sheer weight of shells and men. A new force was created for this purpose: the Sixth Army, under General Ettore Mambretti. The target was a chain of four peaks that had to be approached over open, steep terrain.

Low cloud cover meant that Italy’s guns and mortars could not target the enemy wire. The general commanding the division directly below Ortigara realized the implications, and asked permission to delay the assault. This was refused by Mambretti, who was unaware that, as on the Carso, the Austrians had abandoned their trenches and excavated deep caverns for men and artillery, often three meters under the surface. The Austrian gunners on the adjacent summits had excellent sight of the Italian positions and the ground where the Sixth Army had to pass.

Torrential rain had turned the mountainsides to quagmires. The effect was like flypaper: the infantry were trapped under the machine guns, in front of intact wire. Some battalions took 70 percent losses. After three waves of attack, progress was made elsewhere on the line, at immense cost. The survivors spent the night on the mountainside, trapped in front of the wire, pressing their bodies into the gaps between boulders, playing dead under Austrian flares, waiting for the order to retreat. No order came.

The Italians stayed on the mountainside for eight days. When the skies cleared, the artillery opened up and the infantry attacked again, with air support from Caproni bombers. Next day, men of the 52nd Division hacked their way to the summit of Ortigara with daggers and bayonets. They hung on for several days, until stormtroopers swept them off with gas and flame-throwers. The Austrians repeated their success elsewhere on the line. Mambretti ordered a withdrawal to the original positions. The Italians suffered at least 25,000 casualties over the 19 days of the battle, on a front of three kilometers, for no gains.

A captain in the Alpini, Paolo Monelli, recalled that when the last enemy bombardment stopped, ‘ … a vast silence spreads … Then groans from the wounded. Then silence once more. And the mountain is infinitely taciturn, like a dead world, with its snowfields soiled, the shell-craters, the burnt pines. But the breath of battle wafts over all – a stench of excrement and dead bodies.’

Once again, Cadorna let General Capello – now commanding the Second Army – add a new element to the plan without caring how this affected the whole design. For Capello decided that the Second Army, once the Bainsizza had been secured, should wheel northwards toward Tolmein, the only point on the front where Austria still held both banks of the Isonzo. Even with their enlarged forces, however, the Italians could not expect to reduce the Tolmein bridgehead and the hills behind Gorizia while also attacking Mount Hermada, on the southern edge of the Carso.

By early August, Cadorna had more than half a million men ranged along the front, maintaining but not exceeding the 10:4 advantage in manpower that he had enjoyed since 1915. What was new was a crushing superiority in firepower. The factories were working flat out to supply the front with guns and munitions, while Austrian heavy industry had ground almost to a halt. For the first time, the Italians could match the power of offensives on the Western Front.

The fire was so intense that the mountain lost 10 meters in altitude during the battle. Teams of Italian arditi – newly formed shock troops – came close to seizing the summit. At one point, Boroević believed it could not be held.

One of the men ferrying cartridges up San Gabriele was Private Antonio Pardi of the 247th Infantry: slogging uphill with a crate on his back, clambering over the dead, hunching under continual explosions, dumping his crate by the forward positions and half running, half sliding down again in a panic, grabbing at corpses to keep his balance, arriving at the bottom ‘clotted with filth, blood and mud’. Pardi set down his memories fifty years after the event, ‘not out of love for a just and terrible war’, but so that later generations could know what it had been like. ‘Death was so certain that you almost stopped thinking how to avoid it, yet every passing second was another second of life.’

The Italians had suffered 166,000 casualties, including 40,000 dead, of whom 25,000 died on San Gabriele for trivial gains. Some 400 of the 600 battalions involved in the battle had lost between half and two-thirds of their strength. Proportionately, Boroević’s losses – at around 140,000 men – were even heavier, and could not be made good.

The Eleventh Battle was a technical victory that felt like defeat for the Italians. A close bystander who grasped the enormity of this failure was Colonel Gatti, the official historian at the Supreme Command. As the corpses piled up on San Gabriele, he wrote despairingly in his diary: ‘I feel something collapsing inside me; I shall not be able to endure this war, none of us will; it is too gigantic, truly limitless, it will crush us all.’ He found solace in the men’s morale, which was holding up well, he thought. Yet he picked up a sense that their stamina was linked to a mysterious expectation that this would be the final battle. They were making a last colossal effort. What will happen, he mused, when they see that this is not the end?