The accused was charged and tried before us on the following charge:

"That you, Ong Ah Chuan, on or about the 2nd day of June 1977 at about 12.00 noon in front of No. 270, Bukit Timah Road, Singapore, did traffic in a controlled drug specified in Class 'A' of Part I of the First Schedule to the Misuse of Drugs Act, 1973 (No. 5 of 1973) to wit, 209.84 grams of diamorphine without any authorisation under the said Act or the regulations made thereunder and you have thereby committed an offence under section 3(a) of the Misuse of Drugs Act, 1973 (No. 5 of 1973) and punishable under section 29 of the said Act."

On June 2, 1977 at about 9.15 a.m., acting on information received, Acting Senior Narcotics Officer Yeo Kiah Hee (PW6) and Assistant Narcotics Officer Ramli arrived on their motor-cycle at Block 26 Marsiling Drive, Singapore. They stationed themselves on the ground floor of Block 30 Marsiling Drive and commenced observation on the flat of the accused, No. 235-E Block 26 Marsiling Drive.

At about 9.30 a.m., Yeo (PW6) saw a motorcar No. SX 9098, driven by the accused, arriving at Block 26. The accused parked the car in a lane next to Block 26. He then got out of the car, locked it, and walked towards the lift and staircase landing of the ground floor of Block 26. A few seconds later, the accused was seen by the two officers walking along the corridor of the 5th floor of Block 26 towards his flat and entering it. Yeo (PW6) and Ramli continued to keep observation on the flat.

About an hour later Acting Senior Narcotics Officer, Teo Ho Peng (PW7) and Assistant Narcotics Officer Chua Swab Hai arrived at Block 20 on their motor-cycle. On their arrival they noticed that SX 9098 had been parked in the lane adjacent to Block 26. They signalled their arrival to Yeo (PW6) and Ramli and they too proceeded to keep observation on the accused's flat and motor car SX 9098 from the ground floor of Block 28.

At about 11.25 a.m. the accused was seen leaving his flat alone and walking along the corridor towards the lift and staircase landing. As he entered the staircase landing, he was out of sight of the officers for a few seconds. He was then seen coming out of the staircase landing on the ground floor of Block 26 carrying a plastic bag in his right hand. The accused walked towards car SX 9098. On reaching it he unlocked the front passenger door, placed the plastic bag in the car, closed the door, walked towards the driver's door, unlocked it and got into the driver's seat. He started the car and drove it in the direction of Admiralty Road. The four narcotics officers began to trail the accused's car on their two motor-cycles. The accused proceeded towards the city along Admiralty Road and thence into and along Woodlands Road. At Bukit Panjang Circus, the accused drove into Upper Bukit Timah Road towards Ewart Circus. At Ewart Circus, the car proceeded into Jalan Anak Bukit and thence to Bukit Timah Circus. At Bukit Timah Circus the accused drove into and along Dunearn Road towards Newton Circus. At Newton Circus the car turned left into Bukit Timah Road and stopped in front of No. 270 Bukit Timah Road. Throughout the whole journey which had taken a little over half-an-hour the officers did not lose sight of the accused's car. By this time the four officers, Teo (PW7), Chua, Yeo (PW6) and Ramli, who were close on his tail had also turned left into Bukit Timah Road and stopped their motor-cycles some 10 yards or so behind car SX 9098. The accused alighted from the car, locked it and walked away from it in the direction of the officers. By this time, Yeo (PW6), who had been riding pillion, got off the motor-cycle and proceeded towards the accused. Chua, who had also been riding pillion on the other motor-cycle, joined him. Yeo (PW6) approached the accused and after identifying himself as a Government man, detained him. He then seized a bunch of keys from the accused's hand and proceeded to search him. From the accused's wa