The marine police crews are predominantly Cantonese; first-class seamen and courageous policemen, but at best they can scarcely hope to snare more than a minority of those who are determined to break through the blockade. When the successful ones reach Hong Kong Island or one of the sheltered coves of the New Territories, they are met by friends, relatives or confederates of the smugglers. They vanish into the almost impenetrable masses of Chinese and emerge a few months later to register as residents. In most cases the British have no alternative but to accept them. Many of the police are themselves refugees from Red China. They perform their antismuggling duties conscientiously, but if refugees get through despite their best efforts and vigilance, they may be something less than heartbroken. Protection of the land border with Red China is the responsibility of the 200 uniformed men of the Frontier Division, with headquarters at Fanling, four miles south of the border. Measured in a straight line, the border is only thirteen miles long, but 22 miles as it follows a snaky line from Deep Bay in the west to Mirs Bay in the east. On the colony side, it is backed up by a closed zone which varies in depth from a few hundred yards to a mile. No one except police, farmers living in the area, or persons carrying special passes from the Commissioner of Police is allowed to enter or move about in the closed area. Before the dramatic refugee surge of May, 1962, only nine-tenths of the border was fenced on the British side, and the stoutness of the fence was variable—high and topped with barbed wire at some places, but no more than a plain, low fence at others. The storming of the barrier in 1962 caused the British to build an entirely new one which stretched the full length of the border. Crowned with many strands of barbed wire, it stood 10 feet high and was laid out like a long cage, with 20 feet of enclosed ground between the outer, parallel fences. Between the marshlands on the west and the hilly country in the east, the Frontier Division police have three main stations and nine police posts. From each of these, police observers scan the border with binoculars. Foot patrols also keep a continuous watch along the boundary. At night, when the closed area is under curfew, searchlights and dogs are added to the regular patrols. When the integrity of the border is as seriously threatened as it was by the spring invasion of 1962, the closed area may be increased to a depth of three miles, as Governor Black ordered on May 19, 1962.