Televising the courts could lead to “theatricals” from lawyers and offenders and cause “ethical and practical difficulties", the country’s most senior law officer has warned.
Dominic Grieve has put himself directly at odds with the justice secretary, Kenneth Clarke.
Dominic Grieve QC, the Attorney General, said there was a “big question mark” over allowing cameras in to courts.
His warning puts him on a potential collision course with Kenneth Clarke, the Justice Secretary, who announced the plans on Tuesday.
The 85-year-old ban in criminal courts will be lifted initially with the filming of judges’ rulings in the Court of Appeal but will spread to a judge’s sentencing remarks in Crown Courts.
There are currently no plans to film defendants, witnesses or victims but Mr Grieve signalled he would have concerns if there was a further expansion.
His comments followed concerns from politicians and victims' charities that the move risked turning justice into a reality show akin to Judge Judy by providing a platform for offenders or "eccentric" or legal professionals.
Giving evidence to MPs on the Commons Justice Select Committee, Mr Grieve said filming aspects of the trial itself, "in my personal judgment, is impossible and undesirable".
"Clearly all this needs very careful discussion,” he said.
"The question as to whether sentencing remarks should be filmed is in a sense I think, in terms of the validity of the trial process, completely neutral. I don't think it interferes.
"The issue that then arises is, is this going to help public understanding or might it contribute to the whole thing being turned in to a piece of theatre, which might also be undesirable.
"Clearly filming people actually being sentenced is likely to be undesirable as it would probably encourage theatricals, and so for those reasons I think there must be a big question mark over it.”
Mr Clarke wants to remove the ban "as soon as parliamentary time allows" and a consultation process involving the Lord Chief Justice Lord Judge is planned to ensure the move "does not hinder the administration of justice and that it protects victims, witnesses, offenders and jurors", the Ministry of Justice said.
Mr Grieve also echoed the view of Cabinet colleagues that the sentencing by the courts in the wake of the riots was appropriate.
He said tough sentences helped deter others and showed there were serious consequences for anyone involved in the looting and violence.
He said that while some of the offences may have been similar to shoplifting, "participating in a catalogue of offending behaviour that has the capacity to wreck an area's economy and put local people in fear" was clearly an aggravating factor.
Dealing with the riots has cost the Crown Prosecution Service more than £5 million so far, he added.