Britain has a "once in a generation" chance to expose the state failures that allowed widespread child sex abuse to occur, although finding an acceptable figure to head a major public inquiry will be difficult, the government said on Monday.

In recent years, Britain has been left shell-shocked by a series of horrific revelations about decades of nationwide sex abuse, with perpetrators ranging from well-known celebrities to gangs of taxi drivers preying on vulnerable young girls.

An inquiry into the failure of the authorities to stop the abuse, and whether political and establishment figures had played a role in covering it up, was last week thrown into disarray when its second chairman quit before it had even started its work.

"We have a once in a generation opportunity to do something that is hugely important. Together we can expose what has gone wrong in the past," Home Secretary Theresa May told parliament on Monday.

"We can prevent it going wrong in the future. We can make sure people who thought they were beyond the reach of the law face justice."

May ordered the inquiry, expected to last for years, in July in response to revelations of systematic sex abuse involving thousands of young children in towns and cities across the country.

It also followed a number of high-profile celebrity cases such as those of BBC presenter Jimmy Savile, who abused hundreds of victims for decades, and accusations about Cyril Smith, a former lawmaker in northwest England, both of whom are now dead.

The inquiry will look at whether ministers, parliament, police, councils, churches, the BBC and schools among others failed to identify and protect child children from child abuse from 1970 up to the present day.

However, the first chairman appointed by May stood down as just days after her appointment because her late brother was the government's chief legal adviser in the 1980s when some of the abuse cases are alleged to have taken place.

On Friday, Fiona Woolf, the Lord Mayor of London, also quit because of victims said they had no confidence in her because she was too close to a former government minister likely to be an important witness at the inquiry.

"Almost four months after I announced my intention to establish a panel inquiry, it is obviously very disappointing that we do not yet have a panel chairman and for that I want to tell survivors I am very sorry," May said.

"To put it bluntly .... it will not be straightforward to find a chairman who has both the expertise to do this important work and has had no contact at all with an institution or an individual about whom people have concerns."

In a direct message to the victims of abuse, many of whom fear the establishment will protect senior public figures they say were involved in abuse, May vowed: ""I am as determined as you are to get to the truth."

(Reuters)