The United States' use of the phrase "war on terror" may have backfired, Britain's foreign secretary said Thursday.

David Miliband said he agreed that the expression had some merit insofar as it captured the urgency of the situation immediately following the Sept. 11, 2001, attacks. But he said that the phrase, a favorite of the George W. Bush administration, was ultimately "misleading and mistaken."

"The idea of a 'war on terror' gave the impression of a unified, transnational enemy, embodied in the figure of Usama bin Laden and Al Qaeda. The reality is that the motivations and identities of terrorist groups are disparate," Miliband wrote in The Guardian newspaper.

"The more we lump terrorist groups together and draw the battle lines as a simple binary struggle between moderates and extremists or good and evil, the more we play into the hands of those seeking to unify groups with little in common," he said.

Bush first used the expression "war on terror" shortly after the Sept. 11 attacks on New York and Washington, and it still has wide currency in the United States. But many British officials have dismissed the concept as vague and simplistic.

In 2006, Britain's Foreign Office reportedly instructed politicians and diplomats to avoid using the phrase. The linguistic break was made official by cabinet minister Hilary Benn, who told a New York audience in 2007 that the U.K. did not use the expression "because we can't win by military means alone."

A report put out later that year by a committee of British lawmakers said the "war on terror" vocabulary had sown resentment across the Middle East.

In his editorial, Miliband said the correct response to terrorism was to champion the rule of law — adding that he welcomed U.S. President-elect Barack Obama's commitment to close the U.S. prison camp at Guantanamo Bay in Cuba.