The calls came in the wake of a rebuke by Judge Daniel Rodwell for the jurors at Luton Crown Court, who told them that they may have reason to "reflect" on their acquittal of Constable Andrew Taylor, 31, for assaulting Kenneth Whitaker, 67.
The pensioner, from Bedford, was blinded in one eye and needed hospital treatment after twice being squirted in the face with the spray when he parked on double yellow lines.
PC Taylor, 6ft 2in, had denied causing actual bodily harm and said he used the spray because Mr Whitaker, was unco-operative, abusive and threatening.
After the jury's decision, which came following a four-and-a-half-hour retirement the judge said: "Notwithstanding the verdict, this has been a disturbing and upsetting case. I fear that the reaction in the civil court will be quite different and will cost Bedfordshire Police Authority quite a lot of money."
He refused to award PC Taylor costs and told the jury: "I think you will perhaps reflect that if in future other OAPs are gassed or assaulted by police they may indeed have this particular case in mind. It would be totally wrong to fund this defendant's cost out of public money." However, it emerged afterwards that Mr Whitaker had already been paid thousands of pounds in compensation by Bedfordshire police in an out-of-court settlement of a civil action against them.
The Liberal Democrat home affairs spokesman, Richard Allan, said a full investigation was needed: "CS gas was introduced to protect police officers from potentially dangerous assailants. It is hard to see how a pensioner in a parked car could ever be regarded as falling into that category."
The Labour MP for Bedford, Patrick Hall, said he would be seeking an urgent meeting with Mr Straw. He said: "The jury's decision is inexplicable. It seems to imply that it is acceptable for the police to assault a pensioner who is sitting in his car with is seatbelt on."
The civil rights group Liberty called for police use of CS spray to be suspended.
Mr Whitaker's sons, Vince and Kelvin, and his daughter Jennifer, who were in court, said they were shocked. "He was a 65-year-old man sitting in a car with a seatbelt on who was sprayed because a policeman was scared. I have no faith in the justice system any more," said Ms Whitaker.
Mr Whitaker, who was not in court to hear the verdict, said later: "I am just disgusted by it. Nobody is a winner here."
PC Taylor was driven away from court in an unmarked car by a uniformed traffic policeman after leaving the court with his wife Rebecca, who is also a police officer, and their five-month-old son Daniel.
A spokesman for Bedfordshire police said PC Taylor, who has been suspended pending the outcome of the court hearing, would be reinstated to the force and would not face any disciplinary action. He said the force would "look again" at their CS spray procedures but stressed that officers acted within legal guidelines laid down nationally when using their sprays.Reuse content