A former army intelligence officer has claimed he was told to stop investigating sexual abuse at a boys' home in Belfast in the 1970s.

Brian Gemmell told the BBC he was ordered to halt his investigation into Kincora Boys' Home by a senior MI5 officer in 1975, after he presented a report on the allegations.

In 1981, three senior care staff at the east Belfast home were jailed for abusing 11 boys and it has been claimed that people of the "highest profile" were connected.

Mr Gemmell claimed he found out about the abuse through two sources, including an agent called Royal Flush, while he was gathering information about loyalists.

The claims come during a public inquiry in Northern Ireland into institutional child abuse between 1922 and 1995.

The inquiry faced possible suspension last month due to a lack of money as coalition parties were at loggerheads over the latest budget.

Retired judge Sir Anthony Hart, who is leading the Historical Institutional Abuse Inquiry, has said the inquiry "does not have sufficient powers" in its present form to investigate issues relating to the army or MI5.

He said: "There may be benefits to the UK-wide inquiry examining the relevant allegations into Kincora Boys' Home."

Northern Ireland's First Minister Peter Robinson said he wanted a full investigation into the abuses that occurred in Kincora.

He said: "Having received this communication from Sir Anthony, it is clear that the proper route to fully investigate the abuse at Kincora Boys' Home is to have it included in our United Kingdom's Child Abuse Inquiry.

"I will be writing to the Prime Minister and alerting him to Sir Anthony's concerns.

"I will be urging the Prime Minister to ensure that Kincora is included in the terms of reference governing the inquiry established by Her Majesty's Government."

Regarding being told to stop investigating, Mr Gemmell said: "I was summoned to go and see him (the MI5 officer). I went up thinking he was going to be pleased with me.

"He bawled me out. He was rude and offensive and hostile.

"He told me not just to stop any investigation into Kincora, but to drop Royal Flush."