LONDON (Reuters) — British Interior Minister John Reid’s assured handling of a suspected Islamist plot to blow up airliners over the Atlantic has strengthened his credentials to succeed Tony Blair as prime minister.With both Blair and his expected successor, Finance Minister Gordon Brown, on holiday, Reid took centre stage when police arrested 24 plot suspects in overnight raids last week.

Reid, a tough 59-year-old Scot, dominated broadcasts, briefing the public on the investigation and emergency airport security measures in a calm, reassuring way.

Deputy Prime Minister John Prescott, supposed to be running the country while Blair was sunbathing in the Caribbean, was said to be furious at being elbowed aside by Reid.

Newspapers described Reid’s manner as “presidential” and his appearances fuelled talk that he could challenge Brown for the leadership of the ruling Labour Party when Blair steps down some time before the next general election, expected in 2009.

“He’s always seen himself as a possible candidate,” said Wyn Grant, politics professor at Warwick University.

“Clearly Gordon Brown is in a very strong position to succeed Blair, although he is likely to be challenged by a candidate from the left. Reid would be a very different candidate, he would have credibility,” said Grant.

The Scotsman newspaper ran an editorial asking if Reid was heading for the prime minister’s office and the Daily Mail said Brown saw Reid as his “only credible rival” for the Labour Party leadership and with it the post of prime minister.

Bookmakers William Hill slashed the odds on Reid succeeding Blair, prime minister for the last nine years.

But Brown remains the firm favourite with both bookmakers and political analysts, who underlined the difficulties Reid would face in running for the party leadership.

“In the absence of a serious mistake or health problem, I just don’t see how anybody is going to beat him,” John Curtice, politics professor at Strathclyde University, said of Brown, Blair’s heir apparent since Labour came to power in 1997.

Blair, who led Labour to a record third successive general election victory last year, has said he will not seek a fourth term. He is keeping people guessing about when he will step down, though many party members believe he will quit next year.

Blair’s popularity has slumped after a series of government scandals over sex, sleaze and mismanagement.

He has alienated many in his party with his support for US President George W. Bush over the Iraq war, his refusal to call for an immediate truce in the Lebanon war and his backing for more market-style competition in health and education.

Before Blair led his reforming “New Labour” to power, he is said to have assured Brown he would one day step aside for him, and the idea of a Brown succession has become so entrenched, the emergence of a serious rival would be a political earthquake.

So far, only left-wing MP John McDonnell has said he will contest the leadership and he is not seen as a threat to Brown.

Reid, a Blair ally who has adroitly handled a series of tough ministerial jobs including Northern Ireland, health, defence and now interior, would be a different matter.

Although Blair has publicly backed Brown, many suspect that he wants to protect his reformist heritage and fears Brown would revert to more left-wing, “old Labour” policies.

Curtice said some Blair allies would like an alternative to Brown as next leader of the party.

Lance Price, a former media adviser to Blair, writing in The Guardian newspaper before the bomb plot crisis, urged Education Secretary Alan Johnson, a rising star, to run for the leadership, saying that if he did, others would follow suit.

But political analysts said a leadership challenge could be risky for Reid, jeopardising his political future if he lost. His candidacy depends on how well he performs as interior minister and whether he believes there is serious opposition to Brown outside the left of the party, Grant said, estimating the chances Reid would run at one in three or four.

David Denver, politics professor at Lancaster University, said Reid’s performance had been “really impressive” but doubted he would contest the leadership, given his age and the strength of Brown’s position.