“Mr Sawle’s boat is below the wall, Captain!” Allday sounded tense.

“Good.” He accepted Allday’s word, for there was nothing but the slash of black shadow at the foot of the fortress to distinguish boat from entrance.

A midshipman squatting by his feet yawned silently, and Bolitho guessed he was probably fighting his own sort of fear. Yawning was one of the signs.

He said quietly, “Not long now, Mr Margery. You will take charge of the boat once the attack is begun.”

The midshipman nodded, not trusting himself to reply.

Allday stiffened. “Look, Captain! There’s a boat to the left of the wall!”

Bolitho saw the telltale froth of oars and guessed the garrison had taken the precaution of having a guardboat patrolling around the bay. Probably it was intended to prevent any attempt at cutting out the anchored brig, but it was just as deadly as an army of sentries.

Up and down, the oars dipped and rose with tired regularity, the green phosphorescence around the stem marking the boat’s progress better than daylight.

The movements halted, and he guessed they were resting on their oars, letting the current carry them along before starting on the next leg of the patrol.

Allday muttered between his teeth, “Mr Sawle should have the charge laid by now.”

As if in response to his words there was a brief, spurting gleam of light like a bright red eye below the wall, and Bolitho knew Fittock had fired the fuse. The light would be hidden from the guardboat by the wall’s curve, but once Sawle’s men pulled clear the alarm would be sounded.

Bolitho bit his lip, imagining Sawle and his men clinging against the great iron portcullis, listening for the guardboat moving again and hearing the steady hiss of the lighted fuse.

Almost to himself he said, “Come on, man, get away from it!” But nothing happened to break the dark patch beneath the wall.

There was a sudden jarring thud and he saw the eyes of the nearest oarsman light up with an orange glow, as if the sailor was staring directly at a freak sunrise. He knew it was the reflected glow from one of Inch’s mortars beyond the opposite headland, and as he swung round in the boat he heard a sharp, abbreviated whistle, like a marsh-bird disturbed suddenly by a wildfowler. The crash of the explosion was deafening. He saw the far side of the fort light up violently, the billowing smoke very pale before darkness closed in again, leaving him momentarily blinded.

But it had been long enough to tell him Inch’s first shot had been near perfect. It had hit the fortress on the opposite rampart, or perhaps below the wall itself. He could hear the grinding sounds of falling masonry, the splash of larger pieces hitting the water.

Another thud, and the next shot fell in much the same place as the first. More crashes and rumbles, and he saw the smoke drifting in a thick bank low above the bay like a dust cloud.