The decision in Sun’s case was announced by the Court of Arbitration for Sport (CAS) on Friday (February 28).

Sun received the maximum eight-year sanction for a second doping offence and will not be able to return until February 2028.

The CAS panel upheld an appeal by the World Anti-Doping Agency (WADA) against a decision from the International Swimming Federation (FINA) to let Sun off with a warning after finding him guilty of tampering with the doping control process.

It followed a member of Sun’s entourage destroying his blood vial with a hammer during an attempted drugs test in September 2018.

The decision, which came after a 10-hour public hearing in November, effectively ends Sun's career and rules him out of competing at this year's Olympic Games in Tokyo.

CAS ruled the 28-year-old had "failed to establish that he had a compelling justification to destroy his sample collection containers".

His vial was smashed with a hammer on the instruction of Sun's mother.

Zhang Qihuai, a lawyer for Sun, has confirmed the swimmer will appeal the verdict to the Swiss Federal Tribunal.

Zhang released a statement which alleged the decision to ban Sun had been based on “false evidence”.

“February 28, 2020 was a dark day,” Zhang wrote, according to the South China Morning Post.

“It shows the scene where evil defeats justice and power replaces self-evident truths.

“On this day, CAS listened to prejudice, turned a blind eye to rules and procedures, turned a blind eye to facts and evidence, and accepted all lies and false evidence.”

The CAS hearing, which was held in public, saw the 11-times world champion protest his innocence and claim the officials' credentials did not adhere to anti-doping regulations.

The CAS panel had agreed with WADA that the accreditation of the doping control officer at the centre of the row which led to the vial being smashed were in line with international standards.

Sun, the subject of protests from rival swimmers after he won two gold medals at last year's FINA World Championships, appeared evasive under questioning and irked the panel's President Franco Frattini by attempting to bring a member of the gallery into proceedings to translate his closing statement.

The controversial swimmer, one of the biggest names in the sport, had requested the hearing be held in public.

Sun will keep the two titles he claimed at the World Championships in Gwangju, CAS also confirmed.