Tony Blair has “no credibility” left in the Middle East as rumours continue to circulate that the former British leader will step down after eight years as the region’s envoy.

Reports of the former British prime minister’s resignation amid a lack of success come as a former UK ambassador to Libya claims his appointment was a “mistake” and a US official described him as a “standing joke” in the region.

It is thought that Mr Blair is preparing to step back from his diplomatic role as the official envoy for the Quartet Middle East Peace Negotiators, a foursome - including the United States, the European Union, United Nations and Russia - involved in mediating the peace process in the Israeli-Palestinian conflict.

Mr Blair has allegedly recognised that a frontline role is no longer possible as criticism mounts of his sprawling business interests and poor relations with the Palestinian Authority, according to insiders.

Reports indicate that Mr Blair has met US Secretary of State John Kerry and the EU’s foreign policy chief Federica Mogherini to discuss a possible job change.

“It is long overdue,” one diplomat, briefed on the on-going talks, told the Financial Times. “He has been ineffective in this job. He has no credibility in this part of the world.”

Tony Blair meeting troops in the port of Umm Qasr, Iraq in May, 2003 (PA)

“Tony Blair is neither an asset nor a liability but his current role is no longer viable,” another individual close to the Obama administration scathingly claimed.

It comes amid mounting concerns over the multi-millionaire’s business interests in the region. Mr Blair’s corporate roster has included PetroSaudi, an oil firm linked to the Saudi royal family, finance giant JPMorgan and Mubadala, an Abu Dhabi wealth fund. Additionally, Mr Blair’s relationship with officials from the Palestinian Authority was strained from the outset thanks to his pronounced support for the Iraq war and last year allegations surfaced indicating he had agreed to advise Egyptian president Abdel Fattah el-Sisi.

The Iraq War: A timeline Show all 16 1 /16 The Iraq War: A timeline The Iraq War: A timeline 11 September 2001 Terrorists belonging to al-Qaeda use hijacked aeroplanes to kill 2,996 people in attacks on the east coast of the US. AP The Iraq War: A timeline 12 September 2001 Tony Blair promises George W Bush that the UK will support the US, whatever the President decides to do. AFP/Getty Images The Iraq War: A timeline 25 March 2002 Jack Straw, Foreign Secretary, warns Blair that invading Iraq would be legally dubious. Getty Images The Iraq War: A timeline June 2002 Tony Blair asks defence officials to outline options for UK participation in military action against Iraq. afp/getty images The Iraq War: A timeline 24 September 2002 The government publishes a dossier about the threat from Iraq’s weapons of mass destruction. A foreword by Tony Blair states that Saddam Hussein’s “military planning allows for some of the WMD to be ready within 45 minutes of an order to use them”. It is subsequently alleged that this dossier was “sexed up” for political reasons. Getty The Iraq War: A timeline 2 October 2002 Congress authorises President Bush to use military force against Iraq. Getty The Iraq War: A timeline 8 November 2002 UN Security Council passes resolution 1441, insisting that weapons inspectors be allowed back into Iraq and calling on the regime to give up its WMD or face the consequences. Simon Walker/AP The Iraq War: A timeline 18 July 2003 David Kelly, an expert in biological warfare, is found dead after being named as the source of quotations used by the BBC’s Andrew Gilligan to suggest that the dossier of September 2002 had been “sexed up”. Lord Hutton is appointed to chair a judicial inquiry into his death. GETTY IMAGES The Iraq War: A timeline 13 December 2003 Saddam Hussein is captured near Tikrit, after nine months in hiding. REUTERS The Iraq War: A timeline 2 March 2004 Bombings in Baghdad and Karbala kill nearly 200 people: the worst attacks since the fall of Saddam. Getty Images The Iraq War: A timeline 14 September 2005 Bombs in Baghdad kill 160 people and injure more than 500. EPA The Iraq War: A timeline 30 December 2005 Saddam Hussein is executed. Getty Images The Iraq War: A timeline 28 May 2009 The last British combat troops leave Iraq. Getty Images The Iraq War: A timeline 24 November 2009 The Chilcot inquiry holds its first public hearing. Getty The Iraq War: A timeline 2 February 2011 The Chilcot inquiry holds its final public hearing. AFP/Getty Images The Iraq War: A timeline 21 January 2015 Sir John Chilcot confirms that his report will not be published before the general election in May 2015. Getty Images

Speaking last week, an official claimed as the last round of 2013 failed negotiations began – shortly after Mr Kerry’s appointment – the former leader had become a “standing joke”.

“He showed up, but was not effective,” the senior former official told the Daily Telegraph.

“Honestly, when the Kerry negotiations were going on, it was like he’d wait until Kerry was going to be in the region and show up at the same time and then do press releases. It was sort of unseemly.”

After a decade as British prime minister his appointment in 2007, at the behest of George W Bush’s administration, was met with disbelief in some quarters.

Oliver Miles, previously head of the Foreign Office’s Near East and north Africa department, expressed surprise that Mr Blair had ever been appointed on the BBC’s Today programme earlier this morning, calling it a “very strange appointment in many ways.”

“I think it’s a mistake. He’s the wrong man. I find it hard to believe, frankly, that the British Government would support him having a wider role,” he said in a wide-ranging attack on the former leader.

Tony Blair speaking at the Chilcot inquiry in 2011 (Reuters)

“I think he’s not been able to do the job. I think he’s the wrong man and I also think it’s the wrong job,” Mr Miles added.