BBC Director General George Entwistle was accused by MPs of failing to "get a grip" and compared to James Murdoch during a stormy select committee session in the wake of the Jimmy Savile sex abuse allegations.
He was also accused of "an extraordinary lack of curiosity" over Newsnight's investigation into Savile.
The BBC boss denied the corporation handled the "unprecedented" Savile sex abuse scandal badly as he appeared before MPs on Tuesday - but conceded part of their response had "taken longer" to do than he would have liked "in a perfect world."
The director general of the BBC, speaking to the House of Commons' culture select committee revealed they were “looking at between 5 and 10 serious allegations [involving past and present employees of the BBC] relating to activities over the Savile period.”
He said it was a "matter of regret and embarrassment" that the corporation had to correct a blog by Newsnight editor Peter Rippon on why his programme pulled an investigation into the former TV presenter, in the wake of an investigation into the BBC 2 flagship news show by BBC 1's Panorama.
Entwistle added that in wake of watching Panorama, which was seen by 5.1m Brits, he believed the Newsnight investigation into Savile "should have been allowed to continue."
On Monday Newsnight editor Peter Rippon stepped aside after the BBC said his explanation of why the show dropped its investigation into Savile was "inaccurate or incomplete".
During the evidence session Entwistle told MPs he believed the BBC's head of news, Helen Boaden, had spoken to him about Newsnight looking into claims against Savile - but he said he did not speak to those making the film.
He said he felt it was better to operate through the BBC "chain of command", so that he could remain an impartial judge of any subsequent disciplinary case, and had therefore left it to Boaden and deputy director of news Stephen Mitchell to deal directly with the programme.
"Helen said to me, I wanted to tell you that Newsnight are looking at Jimmy Savile and if it comes off, if it stands up, it may have an impact on your Christmas schedule, and I said 'thanks for letting me know, please update me' and what I meant by that was, let me know if it's going ahead," he said.
"The key message I took away from the conversation was that it wasn't clear to Helen whether it was going to stand up or not... That was the key burden of the conversation that I took away. We never spoke about it again, from which I inferred that the decision had been made not to proceed with it."
On Rippon's blog, he said: "As I’ve explained, I absolutely would have expected the editor of a programme to have given a definitive and factual accurate account of what happened on that programme.”
Entwistle told MPs: "There is no question, what Jimmy Savile did and the way the BBC behaved in the years, will raise questions of trust for the BBC. This is a gravely serious matter and one cannot look back on it with anything other than horror."
He said he thought the culture had changed but added it may not have "as much as it should."
"We have asked Dinah Rose QC to come and work with us to look at how our handling of sexual harassment charges of any kind is working," he revealed.
The BBC's head also said it was as not clear if child abuse was "endemic" at the BBC.
Entwistle said it was "deeply regrettable" that a blog published under Mr Rippon's name turned out to be inaccurate.
The blog suggested that the Newsnight inquiry was principally into the handling of a Surrey Police investigation into Savile and appeared to indicate that reporters had not turned up significant new information. It was later relied upon by management in setting out the BBC's position.
Entwistle said he was "very disappointed indeed" to learn that it was incorrect.
"What I relied upon is something that in my BBC career I've always been able to rely upon, which is the editor of a programme having a full grip and understanding of an investigation they were in charge of," he said.
"In this case that doesn't appear to have been the case, and that is disappointing."
In a blog for The Huffington Post UK after the hearing, Labour MP Ben Bradshaw, who sits on the culture committee, wrote: "My instant verdict on George Entwistle - the BBC Director General - after his appearance before our committee today is of a good, decent man, new to the job, grappling with the BBC's horrendous bureaucracy who has been badly let down by others, and may still be being so."
CATASTROPHIC: How MPs Laid Into Entwistle
"Do you now accept the decision to drop the Newsnight investigation was a catastrophic mistake?" - Labour's Ben Bradshaw
"Does that not make it all the more important that you get to grip with the facts, that you assemble the facts yourself and act on those facts decisively before this report comes out?" - Ben Bradshaw
"You sound like James Murdoch now" - Conservative MP Damian Collins
"It appears that your determination not to show an undue interest applies to everything at the BBC, from today's performance" - Conservative MP Philip Davies
"Are there any other questions you would like us to remind you to ask?" - Philip Davies
Jimmy Savile in 1961 around the time he was working for Radio Luxembourg. He is at London Airport with Pan American stewardess Birgit Johansson with two gold discs; one is for American singer Elvis Presley for having sold one million copies of "It's Now or Never" in the UK, and the other is for Presley's manager, Colonel Tom Parker
Cilla Black and Jimmy Savile before a Variety Club Luncheon at the Savoy Hotel. Taken in 1964, the year Savile became the first presenter of Top of the Pops
Two women have come forward with allegations from the 1960s, one who was 14 and another who was a teenager when she claims Savile sexually abused her in Scarborough
Savile in 1969 with Physically Handicapped and Able-Bodied (PHAB) member Erika Mentz from Germany and other PHAB members at a dance at Devonshire House
1969 also saw Savile begin volunteering at the Stoke Mandeville Hospital for specialist spinal injuries. He would later be given a room there
Jimmy Savile presenting a cheque to children on behalf of the NSPCC in 1969
The 1970s saw Savile start volunteering at Leeds General Infirmary and...
... Broadmoor secure high-security psychiatric hospital. Allegations by former patients have been made against Savile although ex-workers have disputed the idea that he could have been left alone with anyone whilst working there
The 70s also saw the start of Jim'll Fix It. Allegations from this period include Caroline Moore, a 13-year-old patient at Stoke Mandeville hospital in 1971, who says Savile "rammed his tongue" down her throat and another allegation accuses Savile of molesting a brain-damaged teenage patient at Leeds General Infirmary in 1972
The 1980s saw the continuation of Top of the Pops and Jim'll Fix It as Savile became a much loved household name. Two allegations relating to this time include one from a then-15-year-old girl (not pictured) who made a complaint of abuse by Savile in Lancashire. Pictured is 12-year-old Rebecca Heap
Savile at the Stoke Mandeville hospital with injured children from Beirut in 1987
Savile was knighted in 1990 and continued his charity work throughout the decade
Savile was questioned in 2007 by police about allegations of sexual abuse but the Crown Prosecution service says there is not enough evidence to warrant a prosecution
A 2008 police report into abuse at the Haut de Garenne children's home in Jersey names Savile, although this is never made public
Savile re-united with his Jim'll Fix It chair in 2009. The previous year Sussex police received a complaint of sexual assault but went on to say the victim was "unwilling to co-operate in any investigation"
Jimmy Savile is found dead at the age of 84 in October 2011. He is buried in Scarborough
In December 2011 the BBC drop an investigation by Newsnight into the allegations of sexual abuse by Jimmy Savile. Three tribute programmes are aired instead
ITV airs a documentary, 'Exposure, the Other Side of Jimmy Savile', in which a number of women claim they were abused by Savile as youngsters, including Karin Ward (pictured)
Within days of the documentary, many more allegations surface. By the 9 October Peter Spindler of the Metropolitan Police tells the BBC: "It is quite clear from what women are telling us that Savile was a predatory sex offender"
11 October 2012 and George Entwistle, Director General of the BBC, asks journalists why the Newsnight programme was dropped as police from Tayside, Greater Manchester, Lancashire and North Yorkshire police say they are investigating allegations going back to 1959
12 October and police reveal they have 340 potential lines of inquiry
15 October sees a man come forward alleging that Savile abused him when he was a nine-year-old boyscout
Savile's family removed his headstone from his grave and broke it up in the wake of the furore
Jimmy Savile sexually abuses transgender man
A transgender man comes forward alleging that Jimmy Savile 'stuck his hand up his nightdress' while he was a 17-year-old teenage girl at Broadmoor in the 1970's. More here http://www.huffingtonpost.co.uk/2012/10/15/jimmy-savile-timeline-abuse-allegations_n_1966426.html?1350304573#slide=1641388