British security services may have known that children were being abused at a notorious boys' home in Belfast and used the information to blackmail the paedophiles, a public inquiry heard today.

The Historical Institutional Abuse Inquiry will investigate whether the State helped to 'connive, collude, orchestrate, utilise, exploit or cover up' years of abuse at the Kincora Boys' Home in the 1970s.

The hearing was told today that the name 'Kincora' had become synonymous with claims of abuse and official cover-ups.

It has long been alleged that a high-ranking paedophile ring operated out of the former boys' home during the 1970s.

Abuse: It has long been claimed that a high-ranking paedophile ring operated at Kincora Boys' Home, pictured

It is also claimed that the UK security services knew about the abuse but did nothing to stop it, instead using the information to blackmail the influential men involved, including senior politicians, to get information from them.

In 1981, three senior care workers at Kincora were jailed for abusing boys - one of whom, William McGrath, was believed to have been an MI5 agent.

Barrister Joseph Aiken, counsel to the long-running inquiry, said: 'Although it is an established fact that children were abused by staff in Kincora, this inquiry in addition has to address, amongst others, a range of extraordinary allegations.

'Not that the State failed to prevent abuse because of missed opportunities or ineffective systems of oversight and regulation but that it, with deliberation and planning, cynically orchestrated and utilised the abuse of children it was supposed to care for in order to further its own ends.

Victim: Clint Massey, a former resident of the home, pictured outside the public inquiry today

'If true, that would mean those who had the privilege and responsibility of protecting citizens compounded the pain of those who suffered as a result.

'If the allegations are no more than rumours and suspicion, they have the effect of heaping further unnecessary misery on the victims of abuse in Kincora.'

The HIA inquiry was set up by the government of Northern Ireland in 2014 to examine harrowing allegations of physical, emotional and sexual abuse at state- and church-run institutions between 1922 and 1995.

It is being chaired by retired High Court judge Sir Anthony Hart, who is sitting alongside senior social workers Geraldine Doherty and David Lane.

In his opening address, Sir Anthony said a number of state bodies including the Royal Ulster Constabulary, MI5, MI6 and the Northern Ireland Office would be examined.

The inquiry has received 'full and voluntary' co-operation from all government departments and agencies, he added.

Sir Anthony said: 'Not only have we been able to inspect the material they have provided at our request, which includes material that we were able to identify from the material already provided by them that might also be relevant, but we are going to examine the relevant material during these public hearings.'

However, a number of individuals including unionist Roy Garland, ex-Army intelligence officer Brian Gemmell, and former Army officer Colin Wallace have refused to give evidence.

Sir Anthony said: 'While it is for them to decide whether they wish to give evidence in person, we regret that they have adopted this position because this is their opportunity to describe in person and in public their experiences in Kincora.'

Inquiry: The panel is handling claims of historic abuse in institutions across Northern Ireland

Campaigners had hoped to have Kincora included in the nationwide child abuse probe chaired by judge Lowell Goddard, which will have the power to compel witnesses.

However, a legal challenge to overturn the Government's refusal was rejected as 'premature' by a High Court judge last month.

The HIA is now in its 15th module and, by the time it concludes public evidence sessions this summer, more than 450 witnesses will have provided oral testimony.

Sir Anthony is expected to submit his findings to the Northern Ireland Assembly by early next year.

Speaking outside the court, Clint Massey, who spent eight months in Kincora aged 16, said he was looking forward to giving evidence next week.

'I will have my day in the sun,' he said.