Kevin Woodburn spoke out after attending the Scottish Parliament where he heard Lothian Labour MSP Kezia Dugdale ask what plans the Scottish Government had to enhance the rights of victims during court procedures.
Shaun was killed by a single punch from a then 16-year-old schoolboy, Mohammed Ibnomer, outside a pub in Leith in the early hours on January 1, 2017.
Ibnomer was sentenced to four years for culpable homicide and Shaun’s family is still trying to discover why the sentence was so short.
Mr Woodburn said: “There are certain things politicians can get involved in and probably quite rightly can’t get involved in.
“But I’m in a position where I want to call into question the entire system. not just the political part of the system, but the entire justice system and the lack of public accountability there is.”
He said he was concerned about the right not just of victims’ families but also right the victims themselves should still have.
“Because someone has died or been murdered should that mean we treat them as any less of a human being or give them less rights as people who are still on the planet?
“My answer to that is no, they should still be afforded certain right, they should still be afforded some common decency.
“That’s where the whole system falls down. There is no real common touch to the system, no real interest in anything other than the legalities of the system.
“The people involved in it maybe need to take lessons from the public at large and there need to be more public involvement in the process.”
He also spoke of his anguish at the fact Shaun was subjected to two post mortems because under Scottish law the defence has the right to a second post mortem.
He said: “Why can we not have a system where representatives from the prosecution and defence are at the same post mortem?
“My son had to endure being cut open and examined again - for what need?
“If there was a dispute over medical things I would understand that - but have both representatives there at the same time. Why is that so difficult?”
He said the second post mortem delayed the release of Shaun’s body to the family and meant Shaun’s funeral could not take place until January 27.
“The whole process just comes across as barbaric, medieval.”