Colquhoun's activity did not stop short at the production of his first book, a work which roused the Government from its lethargy, and which even awakened the interest of the King, he issued a police gazette containing a full description of all known offenders, which circulated in all parts of the kingdom, and was the means of bringing many miscreants to justice; he strongly endorsed Bentham's suggestion that a public prosecutor should be appointed, in order that private persons should be relieved of the odium and expense of coming forward to prosecute offenders, who might enjoy a measure of popularity, or whose conviction might be desirable on public grounds, even if no individual had suffered specific injury; and in the year 1798 he was induced to turn his attention to the question of river-police. The rich cargoes of West India merchantmen lying in the Thames had long offered temptations, and the absence of police gave frequent opportunities which London thieves could not resist. Robberies were of daily occurrence, and the value of the property annually stolen from ships and wharves has been computed at half a million sterling.[178] Under these circumstances, the principal ship-owners, despairing of ever obtaining protection from Government in return for the heavy taxes they paid, applied to Colquhoun to help them to defend their goods. He assented, and produced a work called "A Treatise on the Commerce and Police of the River Thames," which was soon followed by the establishment by Government[179] of an efficient water-police, with headquarters at Wapping, and composed, for the most part, of sailors who had served their time in his Majesty's Navy. In 1821 the Home Secretary, Lord Sidmouth, who had given much attention to police questions, determined if possible to put an end to the discreditable state of the London streets, where of recent years robberies had increased to an alarming extent. With this object in view, he decided to confine the services of the Bow Street patrols to the Metropolis, and gave orders that, in future, the wide circuit they had previously guarded was to be reduced, and their energies concentrated within the circumference of the central region. Dividing this limited area into sixteen districts, he attached to each a party of four men under a Conductor, and retained at Bow Street a reserve of one Conductor and fourteen men at the disposal of the Inspector there, for use in any sudden emergency. The suburbs and outlying districts were momentarily left unprotected by this withdrawal of the Bow Street Officers; so to repair this defect, the Horse Patrol, which in 1805 had been reorganized by Sir Richard Ford, was further improved and its numbers increased. The force was now divided into two branches, the mounted and dismounted, each of which was again split up into four divisions: the strength of the establishment was fixed at 161 of all ranks, apportioned as follows--