SINN Fein and the SDLP have clashed over a controversial British House of Commons report which claims that public inquiries into alleged security force collusion are "financially unsustainable."Earlier this week the Northern Ireland Affairs Committee (NIAC) issued a report claiming that the re-investigation of unsolved Troubles murders was endangering the Police Service of Northern Ireland's (PSNI) ability to carry out its day-to-day duties.The committee, which is made up of 13 MPs from the British House of Commons, claimed that the work of the police ombudsman was also being put in jeopardy by the need to re-examine allegations of police misconduct during the Troubles.The committee further warned that the cost of the Historical Enquiries Team (HET), the body set up to investigate unsolved murders during the Troubles, could spiral to more than 45 million in coming years.Despite the HET re-opening more than 1,100 murder investigations, only one case has been recommended for prosecution so far.However, the committee's most stinging criticism was aimed at funding for public inquiries into high profile killings such as the British army's shooting dead of 14 unarmed civilians on Bloody Sunday and the murders of solicitors Pat Finucane and Rosemary Nelson.It noted with concern that 183 million has already been spent on the Bloody Sunday inquiry. It said that no future inquiries should take place without the agreement of the Northern Ireland Assembly.Republicans say this recommendation would in effect mean an end to all collusion inquiries, as any new inquiry would require the consent of unionist politicians.SDLP deputy leader Alasdair McDonnell, the only Nationalist MP to sit on the committee, said allegations of wrongdoing by the security forces must be investigated, but he does not believe inquiries are the answer."I don't see a lot of demand in the future for further inquiries because I think the public are beginning to be concerned about the substantial amount of money in these inquiries that can go to lawyers and others, but with no direct benefit to the victims or their families," he said.However Sinn Fein hit out at the NIAC report, claiming that it had no credibility with Nationalists."It is not inquiries themselves into the past which cost money, it is the British state policy of concealment and cover-up," said the Sinn Fein Assembly member Martina Anderson."If the British government came clean and told the truth about its involvement in many of these activities then many families would find closure."However what we have witnessed with the British approach to Bloody Sunday and the continuing efforts to frustrate inquiries into the murders of Pat Finucane, Rosemary Nelson and Robert Hamill is a deliberate attempt to suppress the truth."The PSNI continue to deliberately withhold information from a series of inquests into disputed killings."