The captain himself was at the steering wheel of his U-boat.

“Eine Minute bis es explodiert!” he barked to his crew.

“One minute to explosion!” translated Sid.

Upon seeing the three, the captain shouted over the noise of the fire bell ringing, “You cannot stop us now!”

“Eric! The ladder!” shouted Sid. “Climb up and open the hatch!”

The boy ran to the bottom of the ladder, but it had been pushed upwards to be stored. It could only be reached by a grown-up, not a rather short eleven-year-old boy. “I can’t reach!”

Sid charged over to where the boy was standing, but Speer thumped the old man on the back of the head with the butt of his pistol, and he fell to the ground.

THUMP!

“UNCLE SID!” shouted the boy.

The gorilla bared her fangs and snarled at the captain. “ROAR!”

“Don’t worry about me!” called the old man from the floor. “Open that hatch!”

“Gertrude!” shouted Eric.

“Over here! I need your help!”

The gorilla leaped across to the boy.

THUMP!

Eric jumped on her back, and Gertrude leaped up towards the hatch.

BOING!

The boy’s hands grabbed the bottom of the ladder, and it slid down to the floor.

“Thanks, Gertrude!” he said, climbing off the gorilla’s back to scale the ladder.

Then Gertrude jumped down to tend to Sid as Eric tried to open the hatch.

“STOP THAT BOY!” shouted Speer, but his crew were too scared to try to pass this ginormous ape.

“COWARDS!” he screamed, before abandoning his steering wheel. The submarine immediately felt as if it were lurching off course.

CREAK!

The captain raced over and grabbed hold of the boy’s legs.

“NOT SO FAST!” cried Speer, trying to yank the boy down. He’d very nearly done it, but Gertrude had now helped Sid up to his feet, and the old man rushed over to tackle Speer.

“See if he’s ticklish, Uncle Sid!” shouted Eric.

“I am the most highly decorated captain of the entire U-boat fleet!” protested Speer. “I am not ticklish anywhere!”

“Everyone’s ticklish somewhere!” said the boy.

Immediately, Sid went to work, tickling the man’s ankles, then behind his knees, but there was no reaction.

If only Sid had had this handy guide:

If Sid had been in possession of such a guide, he would have known exactly where to tickle Captain Speer. As it was, he tried lots of places to no effect whatsoever, so he called for help.

“GERTRUDE!” he cried.

The gorilla lunged at the submariners to startle them…

“GRRRR!”

…before leaping over to the ladder.

Somehow, the animal knew exactly what to do.

Go straight for the bottom!

Gertrude tickled Speer there for a moment…

TICKLE! TICKLE! TICKLE!

“OH! HA! HA! PLEASE! NO!”

Then she went in for the kill. The gorilla bared her fangs and sank them right into the captain’s buttocks.

CHOMP!

“OOOWWW!” screamed Speer.

The captain immediately tumbled down on top of Gertrude and Sid.

“I’ve nearly done it!” called Eric. “Are you sure I should open this?”

“Scuttling the submarine is our only hope of saving Churchill!” shouted Sid.

So the boy took a deep breath and spun the final lock on the hatch. With all his might, he pushed the hatch against the weight of the River Thames above. But he just couldn’t do it. It was far too heavy.

“GERTRUDE!” he called down.

The ape leaped up on to the ladder. The boy mimed what he was trying to do, and Gertrude nodded her head.

“You are not going to like it, Gertrude. I know you hate water!” said the boy.

The gorilla shrugged. Together they pushed the hatch on the top of the U-boat and let the filthy black water flood in.

SPLOOOSH!

The force of the water washed them both down into the hull.

THUD!

It swept all those in the U-boat off their feet.

SPLOOOSH!

Gertrude screamed, “WHOOP! WHOOP!”

Gorillas can’t swim and the poor creature was up to her waist in water.

“HOLD ON, OLD GIRL!” cried Sid. He grabbed a mop to reach the gorilla. However, while yanking the mop from the catch on the wall, he’d managed to whack the handle on to his forehead.

CLUNK!

The unlucky old soldier knocked himself out cold.

Captain Speer held on to the steering wheel as the water roared in. Struggling against the flood that was drowning him and his U-boat, he reached for a key that was on a chain round his neck, before plunging it into a lock on the control panel.

As he did so, a large button on the panel lit up red and a buzzing sound filled the cabin.

BUZZZ!

“I press this big red button and KABOOM!" announced Speer. “We all die together!”