LONDON — Treasury chief Gordon Brown, expected to succeed Prime Minister Blair by September, suggested yesterday that he would pursue an Iraq policy that is more independent of Washington than the current government.

Mr. Brown acknowledged that mistakes were made in the aftermath of the invasion and promised to be “very frank” with President Bush. He also said that Britain is likely to scale down its commitment of troops to Iraq over the next year — even as the White House is considering dispatching thousands more, at least temporarily.

Mr. Brown’s comments, aired on the British Broadcasting Corp.’s “Sunday AM” program, seemed intended to distinguish himself from Mr. Blair, who has been criticized in Britain for his strong support for Mr. Bush and the war, both unpopular here.

“I look forward, if I am in a new position, to working with the president of the United States, George Bush,” Mr. Brown said. “Obviously, people who know me know that I will speak my mind. I will be very frank. The British national interest is what I and my colleagues are about.”

A spokesman for the American State Department declined to comment on Mr. Brown’s interview.

Mr. Blair has said he will step down as prime minister and leader of the governing Labour Party before September. Mr. Brown, who is credited with helping Mr. Blair reinvigorate the Labour Party, is unlikely to face any credible challenge when the party elects a new leader, who will automatically become Britain’s new prime minister.

Mr. Brown, in the BBC interview, also said Saddam Hussein’s execution — in which Saddam, a Sunni Arab, was taunted with the name of a radical Shiite cleric — had done nothing to help stem Iraq’s sectarian violence.

“Now that we know the full picture of what happened, we can sum this up as a deplorable set of events,” Mr. Brown told the BBC. “It is something, of course, which the Iraqi government has now expressed its anxiety and shame at.”

Mr. Blair, who previously declined to comment on the hanging, said through his press office yesterday that the manner of Saddam’s execution was “completely wrong.”

Mr. Brown also told the BBC that he believed the ideological battle for the hearts and minds of young Muslims was as crucial as the battle against communism was for previous generations.

Mr. Brown, in charge of Britain’s Treasury since 1997, said he had worked with officials across the American political divide and remained close to the former chairman of the Federal Reserve, Alan Greenspan, and a former treasury secretary, Robert Rubin.

In the interview, recorded on Saturday, Mr. Brown also said he believed there should be some form of inquiry into the aftermath of the 2003 American-led invasion.

“There are lessons to be learnt, particularly from what happened immediately after Saddam Hussein fell,” he told the BBC.

“One is that in Iraq itself there is absolutely no doubt — and I think people will agree on this in time — that the passage of authority to the local population should have begun a lot earlier, so they had to take more responsibility for what was happening in their own country.”