A former legal clerk on Thursday pleaded guilty at the District Court to conspiring to pervert the course of justice in a drug-trafficking case that led to the wrongful conviction of his client four years ago.

Chan Keung-lee, 60 and now unemployed, was accused of conning Ma Ka-kin into taking the blame for attempted cocaine trafficking and letting the real culprit, Hung Chi-him, go free.

The court heard that in 2016, Ma, a restaurant worker, allowed his former colleague Hung to use his address to receive a parcel from Brazil, in which customs officers found more than one kilo of cocaine.

Both men were charged in relation to the drugs found in the parcel.

Ma was represented by a legal team that included Chan, which advised him to sign a declaration in 2017 to plead guilty, provided that all charges against Hung were dropped.

But Ma discharged his legal team and retracted the declaration later in the year.

He was found guilty by a High Court jury in 2019 and sentenced to 23 years in jail.

Three appeal judges overturned the verdict in 2021. "It was alleged that the advice he had been given was tainted and motivated by a conflict of interest, since his legal fees were being paid by Hung Chi-him, or those related to, or connected with, him," according to the judgement.

"Whatever happened in this case does not reflect well on the legal profession or the legal system," the judgement added.

Chan's sentencing hearing is set for September 14.