A man allegedly killed by Carshalton cop Simon Harwood at the G20 protests in 2009, died from a heart attack not from his fall, a court heard.

Pathologist Dr Freddy Patel, who carried out the initial postmortem on April 3, 2009, told Southwark Crown Court he stood by his claims despite three pathologists contradicting his findings.

The prosecution claims Tomlinson, 47, died from heart failure caused by internal bleeding associated with his liver after the policeman hit him with a baton on the leg and then pushed him causing him to fall.

Dr Patel told the court he had been instructed to carry out the postmortem examination to help "to rule out any assault or crush injuries" on Tomlinson associated with G20 protests.

The initial postmortem was carried out before the video showing Tomlinson with his hands in his pockets walking away from police and being pushed came to light.

The prosecution say it was a "gratuitous act of aggression" on PC Harwood's part.

In describing to the court his postmortem examination, Dr Patel said he had disposed of bloody fluids found inside Tomlinson's stomach cavity because he had made up his mind about the cause of death.

Dr Patel, a consultant forensic pathologist with 35 years' experience, said he kept about 15ml of the "plum coloured" fluid but poured the rest down a sink.

Mark Dennis QC, prosecuting, asked Patel why he did not keep all the fluid so its composition could be tested at a later date.

Patel told the court: "My impression was that it was more body fluid than blood. Having done my examination and having come to a cause of death in my mind, it was obvious that it could not have been three litres of blood."

The court heard how Dr Patel had failed to mention Tomlinson's baton injuries or his bite from a police dog when drawing conclusions about possible causes of death in his postmortem as he did not think they were relevant.

While his initial report raised the possibility that a fall could have prompted internal bleeding, on seeing the video of Tomlinson being pushed he believed the subsequent sideways fall could have done this.

Harwood denies manslaughter.

The trial continues