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32. As regards the possibility of effecting a landing on the mainland, the Admiralty are of opinion that the difficulty of manoeuvring in the enclosed waters of the bays lying to the north-east of Hong Kong, and the distance of these bays from any place where submarines could seek refuge in time of need, would greatly restrict the scope of their operations in these waters. They consider that presence of a naval defence flotilla would not be an effectual deterrent to attempts to effect a landing in Mirs Bay, or in one of the numerous bays on the Chinese coast lying to the north of Hong Kong.

It will therefore be necessary so to strengthen the force allotted to the defence of the mainland front of the fortress as to enable it successfully to oppose attack by an expeditionary land force of such strength as Japan could bring to bear within a month of the outbreak of hostilities.

33. The General Staff have investigated the conditions limiting the size of the military force that Japan could convey oversea against Hong Kong within a period of one month, and an estimate of the number of troops required to hold the mainland made front of the fortress against such a force. Their conclusions are embodied in a memorandum which is printed as Appendix V to this Memorandum.

It will be seen that they are of opinion that Japan would be able in or after the year 1915 to despatch a force of three divisions with artillery, about 48,000 men, tc the neighbourhood of Hong Kong, and would be in a position to attack the mail defensive position on the mainland covering that fortress by the beginning of the third week from the issue of orders to mobilise. They consider that the total force required to withstand such an attack and at the same time garrison the island would be not less than 18,000 to 20,000 men, of whom at least 15,000 would hold the position on the mainland, the remainder being allotted to the fixed defences and to the defence of the island, upon which feints might be expected.

The net increase to the existing garrison would therefore amount to 14,000 to 16,000 men, with a due proportion of artillery.

IX.-Anti-torpedo Defences.

34. The question of the liability of Hong Kong to attack by torpedo craft has recently been reviewed in the light of the principles laid down by the Admiralty, and in the Colonial Defence Committee's Remarks No. 441 R, dated the 8th November, 1907, on the Defence Scheme revised to 1906, the opinion was expressed that, in view of the existence of numerous conveniently-situated harbours on the Chinese coast, which, in spite of neutrality obligations, an enemy would probably not hesitate to use as temporary torpedo flotilla bases, there are no insuperable difficulties to prevent an enterprising enemy from placing torpedo craft within striking distance of Hong Kong. The Admiralty considered that in the present political situation the liability to such attack was so remote that the provision of special defences to meet this danger was not an immediate necessity. They recognised, however, that changes in the strategic situation in the Far East might take place in the future, which might render necessary the provisions of special defences at Hong Kong to meet attack by torpedo craft.

In these circumstances, the Colonial Defence Committee expressed the opinion that, as it is highly probable that changes in the political and strategic situation in the Far East would develop more rapidly than special anti-torpedo defences could be designed and constructed, the nature of the special defences that might ultimately have to be provided for the protection of Hong Kong against attack by torpedo craft should be considered without delay. They recommended that steps should be taken to obtain information in regard to the practicability of constructing a breakwater on Kellet's Bank to close a portion of the entrance to the harbour, and as to the measure of protection that such a breakwater would afford to His Majesty's ships lying in harbour against attack by torpedo craft.

35. This question was accordingly referred to the local authorities for considera- tion.

A despatch from the Governor of Hong Kong dated the 5th October, 1908, which is printed as an Appendix IV to this Memorandum, serves to confirm Admiral Lambton's view as to the impracticability of constructing a breakwater at the western entrance of the harbour and as a protection against torpedo attack.

Admiral Lambton considers :--

"That the inen-of-war should not remain at night in their present anchorage, which offers every facility for a successful torpedo attack, but lie at a position removed from the trade of the town and whence they could easily proceed into the open sea.

[515]

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