TNAG-0417-FCO40-463-Review-of-narcotics-problem-in-Hong-Kong-1973 — Page 72

CONFIDENTIAL

DDA/64 3/69/22

N Rolph Esq

Commissioner of Narcotics

Secretariat for Home Affairs

Hong hong

41

155

HKK 19/3

25 September 1973

62

(

Dear Norman

At our meeting in June I undertook to make enquiries in the United Kingdom about various ideas for helping with the detection of drug offences or offenders in Hong Kong. Sone of these are referred to in your report of the meeting which you have sent to the Foreign and Commonwealth Office and which I have seen. The Foreign and Commonwealth Office will, I understand, be commenting upon the broad issues raised by your report, and this letter should be taken as being a response to the matters of detail raised therein. I am sending a copy to Stuart in the liong Kong Department.

TRAWLER TRAFFIC

Scientific experts here think that there may be one or two devices that could be used for keeping surveillance on Thai trawlers. The identity of a number of trawlers is known which have been involved in the Hong Kong run, and it might be possible to get devices on board more than one of them. The main difficulty (and it may be insuperable)

this would, of course, be in getting then onto the suspect trawlers in Thailand; aspect would need prior discussion with people at the Thailand end to see whether it is a possibility. There are also obvious difficulties about security; the

The devices are of discovery of one could lead to the whole lot being discovered. two kinds, one is a sonar device which can be fitted to the hull, the other a radio

Both of transmitter which would have to be concealed above the waterline somewhere. then can be fitted with what is called a transponder device which activates them only when they come into range of a transmitter. This reduces the difficulties over battery size for continuous transmission. The Sonar device would be fairly large, whereas the radio device can, I believe, be made quite small. The sonar device could be used in conjunction with sonar sysplaced in the reception area or with a patrol boat with sonar detection equipment. The sonar buoys have the advantage of being constantly on the watch, but the disadvantage of being stationary (and there may be problems about placing them in international waters); the boat would not be stationary, but it might be difficult to man it around the clock. On the other hand, if there is reasonable intelligence about the departure of a trawler for Hong Kong then using dead reckoning it would be possible to mount the boat watch for a comparatively short period. The radio device could be detected from a plane (with a longish range in good conditions over the sea) or by a receiver placed on a strategic high point on land.

Both of these have the same advantages and disadvantages 23 the sonar device but they do have a longer range. My advisers think that there is enough in the possibilities for it to be worth looking at a bit further. I appreciate that there are enormous practical difficulties involved both at the Thai end end at yours, but if after considering the possibilities at your end, you think it wortli pursuing