Two paramedics giving evidence at a disciplinary hearing of police officers involved in an incident in which a student athlete was paralysed have accused investigators of putting them under pressure to give inaccurate statements.

Caroline Dilley and Paul Sim, of the East of England ambulance service, are credited with saving the life of Julian Cole at Greyfriars police station, Bedford, after the then 20-year-old’s neck was broken and his spinal cord was injured in 2013.

An earlier hearing saw footage of Cole being tackled to the ground twice by police and bouncers outside Elements nightclub in Bedford. The officers involved say that Cole was conscious and able to walk to the police van, where he was arrested. But witnesses say he was dragged there, unconscious and with his head hanging.

Cole suffered a cardiac arrest and stopped breathing. He will spend the rest of his life in a persistent vegetative state.

On the recommendation of the police watchdog, the Independent Office of Police Conduct (IOPC), four officers from Bedfordshire police are facing allegations amounting to gross misconduct for allegedly failing to conduct adequate welfare checks on Cole, lying about the incident to paramedics and investigators, and using excessive force.

Evidence from Sim and Dilley form an important part of the case brought by the force’s professional standards department. But appearing in their uniforms before the hearing in Stevenage on Friday, both distanced themselves from elements of their written and signed witness statements, and said they could no longer reliably remember the incident.

Both complained that a follow-up statement given almost two years after the incident had been the result of “leading questions” by investigators. Dilley also said she felt subjected to emotional blackmail by investigators from the Independent Police Complaints Commission, the forerunner of the IOPC.

She said they told her how Cole’s family needed “closure” over the incident. “I didn’t really feel comfortable [giving the statement] because of the time that had passed,” Dilley said.

She said that while an initial statement she gave around three weeks after the incident had been her recollection of events, the second was the result of an interview in which she was questioned about specific points. “In my mind it felt quite leading ... I was unsure, when I got it back, what came from my memory and what was suggested to me,” she said.

Among the evidence in the case is a letter sent by Dilley’s employers to the IPCC outlining seven points in the statement that she felt needed clarification, most important of which pertained to a conversation she had with PC Hannah Ross, who is accused of lying to paramedics about Cole’s condition. At issue was whether Ross told Dilley that Cole was removed from the van, or whether he got out himself.

Giving evidence, Sim also produced a letter – previously undisclosed – written to his superiors in which he said he felt that his second signed witness statement “doesn’t give a true reflection of events”. Asked why he had signed a statement that did not accurately reflect his memory of the incident, he said: “I suppose being at home I felt under pressure to get it over and done with.”

Sim even suggested that his first statement, given three weeks after the incident, may not have been accurate. In it he said he had spoken to a police officer to get Cole’s immediate medical history; but he said in the hearing that it was possible that his recollection had in fact come from conversations with his colleague about the incident, rather than a conversation with the officer.

The evidence from the paramedics came after a medical expert suggested that Cole had suffered a broken neck when police tackled him to the floor. Prof Charles Davis, a consultant neurosurgeon, said that – on the balance of probabilities – “it was possible but unlikely” that Cole was able to get up and engage in a further struggle if his neck was broken when he was first taken down by a bouncer from Elements.

Emphasising that he could not make a judgment based on solely reviewing CCTV footage, Davis said: “I would say that the fracture is more likely to be an injury sustained later in several injuries – as I understand it from the CCTV – than an earlier injury, because the later injuries, as described, involved movement of the neck.”

He told the hearing that Cole had suffered a “hangman’s fracture” – a shattered vertebrae in his cervical spine, the portion of the spinal column extending from the base of the skull to the top of the chest, which had led to 90% damage to his spinal cord.

A patient with such a fracture may not suffer immediate damage to the spinal cord, and could indeed walk into a hospital, Davis said. But, he added, the pain was “likely to be very severe and the patient [if] fully conscious and not paralysed, might say: ‘I feel like my head’s falling off and I’ve got to hold it and I dare not move it because of the pain.’”

Ross, Sgt Andrew Withey, PC Nicholas Oates and PC Sanjeev Kalyan deny all the accusations. The hearings are expected to continue for another week.