A full independent inquiry into the abuse of residents at a care home for people with learning disabilities has not been ruled out, the Government said today.
Amid Labour criticism that existing investigations did not go far enough, Care Services Minister Paul Burstow insisted that a criminal inquiry must not be prejudiced.
Two more people were arrested yesterday over the controversy at Winterbourne View residential home in Gloucestershire, where BBC's Panorama filmed patients being pinned down, slapped, doused in cold water and repeatedly taunted and teased.
Mr Burstow announced today that Mencap chief executive Mark Goldring had been called in to help officials at the Department of Health investigate the findings of inquiries by the Care Quality Commission (CQC) watchdog and the local council.
But he said the Government wanted to have all the facts of the case before deciding whether to order a full independent review.
Answering an urgent question from Labour in the Commons, he said: "For the avoidance of doubt, we have not ruled out an independent inquiry. A criminal investigation is under way and it is important that we do nothing that could prejudice it."
He added: "Once in possession of the full facts and once the police investigation has concluded, we will be in a position to decide what further action is required."
Today Avon and Somerset Police said they arrested two women yesterday. The women, aged 21 and 22, have since been released on bail.
Last week, another woman and three men were arrested and released on bail.
The CQC issued an unreserved apology last week for failing to act on warnings by whistleblower Terry Bryan about abuse at the home.
Asked about the allegations today, Prime Minister David Cameron said the police investigation was "the most important thing".
"We saw the appalling scenes on our television screens and we need the police to get to the bottom of what happened. If criminal offences were committed, then people should feel the full force of the law coming down on them," he said.
But he brushed aside calls for reform of the CQC regulator in response to its failure to act on warnings from a whistle blower.
"We have got to make sure that the regulator we have in place - particularly the CQC - is absolutely established to do the job we want it to do," said Mr Cameron.
"The last thing we need is another reorganisation of regulators.
"This is now the regulator, this is the responsible body. We have got to make sure they are fully capable of doing all the tasks that are put in front of them."
Labour leader Ed Miliband earlier called for a full independent inquiry.
Speaking at a press conference in London, Mr Miliband said he had been "shocked" by the scenes of abuse filmed at Winterbourne View.
He said that the investigation into what happened could not be left to the CQC and South Gloucestershire Council as both bodies were involved in the failure.
"There must be an independent investigation into what happened and what lessons need to be learned and the Government should announce it straight away," he said.
He added that financiers had "creamed off millions" from Southern Cross care home company while tens of thousands of elderly people had been put at risk and "treated merely as commodities".
With the Government's Dilnot Commission on adult social care due to report next month, Mr Miliband said he wanted cross-party talks on the recommendations for reform.
"We will come to those talks with an open mind about the best way forward, not simply advocating what we have proposed in the past," he said.
"But the principles are clear - high quality care for those that need it, funded in a fair way, with proper accountability for those who deliver the care.
"Let's get round the table, work in the national interest, towards real change which addresses one of the big long-term problems in our country."
Following the financial crisis at Southern Cross, Mr Miliband said the Government should consider whether regulation of the sector should be extended to cover the financial stability of the organisations involved.
He said the collapse of a major provider, responsible for the care of hundreds of thousands of elderly people, could have serious consequences for the taxpayer.
"As we have seen previously with the banks, there are industries - and health and social care services are one such example - where corporate failure can have consequences far beyond the loss to shareholders and investors," he said.
"Just as with the banks, in the end the Government would have to step in and pick up the tab."
Mr Cameron said he welcomed the opportunity for cross-party talks.
"The idea of commissioning Andrew Dilnot was to see if he could unlock this fantastically difficult problem that has dogged governments of all colours for the last few decades," he said
"I am always happy to have cross-party talks, particularly on an issue like that."