London: The biggest scandal in Australian horse racing has led to life bans for trainer Robert Smerdon, his long-term assistant Greg Nelligan and Nelligan’s wife Denise.

The other five members of the Aquanita eight were handed lengthy suspensions by the Racing Appeals and Disciplinary Board at Melbourne’s County Court on Thursday.

Smerdon, the most high profile of the group of trainers and stablehands found guilty of taking part in what the RAD board described as a doping “conspiracy”, was said to be the driving force behind the systematic operation.

Stuart Webb was given a four-year ban for his involvement while Tony Vasil and Trent Pennuto were banned for three and two years respectively.

Trainer Liam Birchley and float driver Danny Garland each received one-year sanctions.

“It was deliberate and sustained conduct,” Jeff Gleeson, counsel for Racing Victoria stewards, said. “It has cast a shadow over thoroughbred racing.”

RV asked the RAD board to fine Smerdon AU$100,000 but a decision will be delayed for 10 days as the board takes into account financial submissions.

The eight had been found guilty earlier in the week of using sodium bicarbonate or other alkalising agents to “top up” horses before more than 100 races over a seven-year period.

None of the eight, who faced 271 charges between them, attended Thursday’s sentencing hearing.