The US has ordered an official review comparing its counterterrorism laws to Britain's as it considers the possibility of toughening its own measures in the wake of the alleged airliner bomb plot.
Attorney General Alberto Gonzales said America "might want to look at" adopting the UK rule that allows terror suspects to be held for up to 28 days without charge.
In the US they must generally be charged a lot sooner, typically within 48 hours - although suspects deemed to be "enemy combatants" have been held far longer without charges being made.
A Department of Justice official said no changes in the law were imminent. "The only thing the attorney general has committed to is a review to evaluate and compare the United Kingdom's counterterrorism laws to those in the United States," he said.
"Any changes to our existing terrorism laws would only be considered after extensive review and discussion to ensure such a change would be necessary, appropriate and constitutional."
Mr Gonzales said of Britain's powers to hold suspects for longer periods: "That may be something we might want to look at.
"But again, is it consistent with our Constitution? We have to look at that."