Sir Ian Blair, the country's most senior police chief, apologised "unreservedly" yesterday for his controversial comments about the Soham murders, but he stood by his remarks over institutional racism in the media.

After some furious criticism, Sir Ian apologised directly to the parents of Holly Wells and Jessica Chapman for saying "almost nobody" could understand why Soham became "the biggest story in Britain".

He told BBC Radio Four's Today programme: "I obviously have to unreservedly apologise to anyone connected to the Soham murders, especially the parents of Holly and Jessica, for reigniting the story.

"It was not intended to diminish the significance of this dreadful crime, which is exactly how I described it yesterday."

But the Metropolitan Police Commissioner insisted his comments about the way race, age and gender played a part in determining which murders were covered by the media were "genuinely true".

The remarks, made at a meeting of the Metropolitan Police Authority on Thursday, sparked a furore yesterday, with some voices backing the commissioner, while others were infuriated by his claims.

Michele Elliott, director of the child protection charity Kidscape, said last night of Sir Ian's Soham remark: "Why was he talking about child murder and trying to make a politically correct point? Has he forgotten about Damilola Taylor and Stephen Lawrence?"

Other campaign groups were also angered by Sir Ian's reference to the Soham case, which dominated the news agenda in August 2002 and subsequently during the murder trial of the school caretaker Ian Huntley.

The case led to an official inquiry about how Huntley managed to get a job in a school, despite a string of allegations of sexual offences against him.

Bob McLachlan, former head of the Met's paedophile unit, had earlier accused the commissioner of having "totally lost the plot", while Dee Edwards, of the campaign group Mothers Against Murder and Aggression, described Sir Ian's comments as "unfortunate".

Support for Sir Ian came from Lord Toby Harris yesterday, a former chairman of the Metropolitan Police Authority (MPA), who said: "All murders are dreadful and have appalling consequences for those affected by them.

"It would be doubly awful if, as a result of that lower level of news coverage, the police took the cases less seriously.

"That is why Ian Blair is right to say that all murders need to get proper attention from the police and the media."

The chairman of the MPA, Len Duvall, said the Met had confirmed it was "categorically untrue" that it targeted more resources at high-profile stories.

He also promised a "reasoned mature debate" about policing and the Press.

Cindy Butts, deputy chairwoman of the authority, whose question at Thursday's meeting sparked Sir Ian's comments, said she "quite frankly" agreed that cases involving white, middle- class victims got more coverage than those with people from ethnic communities.

But Liberal Democrat home affairs spokeswoman Lynne Featherstone said: "The media have, in fact, championed many high-profile murders where the victim was black or Asian, including Damilola Taylor, Stephen Lawrence and Anthony Walker."