"It is not English to strike a prisoner, however," the midshipman reminded him.

For some reason which Mark Redisham did not understand, none of the prisoners were left on board the Dainty. They were distributed among her three consorts, which followed the flotilla towards Harwich, leaving the commodore to return alone to Haddisport.

Skipper Snowling took her northward along the Dutch coast before making a slant across the Silver Pit. He had not gone many miles when a German destroyer came in sight, bearing down towards him.

"Looks as if she was a straggler from that other lot," Snowling continued, and he altered his course to get nearer to a Norwegian steamer to the west of him.

To his surprise and annoyance, the destroyer also altered course and gave chase. Snowling put on more steam, and, as a precaution, got his machine gun ready for action, with Mark Redisham at the breech. In their weeks of mine-sweeping work Mark had proved himself an excellent shot. He had seldom failed to explode a mine when firing at it.

The German signalled to the Dainty to stop and haul down her flag, but the White Ensign remained proudly at the trawler's masthead and her engines never went so well.

The destroyer opened fire and there was an immediate reply from the gun on the trawler's deck. Mark aimed with cool precision and made many direct hits in vital parts, while shots from the German fell thick around him.

The two vessels blazed away at each other as hard as they could for about a quarter of an hour, no great damage being done on either side. But the destroyer, with her greater speed, was quickly overhauling the mine-sweeper, and at last the two came broadside to broadside.

"Look out, chaps!" cried Mark. "She's going to torpedo us!"

All the hands wore their safety collars and lifebelts, and the boat was swung out ready over the quarter rail. The skipper was at the steering wheel.