The war against terrorism is being damaged by the US continuing to run its Guantanamo Bay detention centre, an influential committee of MPs has said.
The Commons foreign affairs committee urged ministers to make UK opposition to the camp "loud and public".
But Tony Blair refused to go further than his previous stance on the camp, telling reporters it was "an anomaly" which should come to an end.
He urged people to remember the terror attacks which prompted its creation.
Earlier, Lord Chancellor Lord Falconer said the UK would never have opened the camp.
And Attorney General Lord Goldsmith said everyone, including terror suspects, were entitled to a fair trial.
In their annual human rights report, the committee of MPs says the continued use of the centre "outside all legal regimes diminishes the USA's moral authority and is a hindrance to the effective pursuit of the war against terrorism".
"We recommend that the government make loud and public its objections to the existence of such a prison regime," say the MPs.
Asked why he would not be more forthright in condemning the camp, Mr Blair said: "I have said why I think Guantanamo is an anomaly and should come to an end".
Earlier, Lord Falconer told BBC Radio 4's Today programme the UK would not have set up the Guantanamo centre.
Lord Falconer said the UK stood by the principles of human rights.
A report for the United Nations last week said aspects of the regime at the camp amounted to torture.
Northern Ireland Secretary Peter Hain also last week said the camp should be closed.
In a speech at the London School of Economics, the attorney general stressed the importance of giving everybody a fair trial.
"There should be in modern society no outlaws; no people to whom the law does not apply... and to whom therefore anything can be done," he said.
