A majority of Democrats in the House of Representatives now support impeaching Donald Trump as Washington reels from allegations that the president improperly pressured Ukraine’s leader to investigate Joe Biden‘s son.

Nancy Pelosi, the speaker of the house, has contacted key allies to gauge whether the party should launch impeachment proceedings.

The senior Democrat has long resisted pressure to impeach the president but is believed to be reconsidering her position in the wake of the Ukraine scandal, according to The Washington Post.

The California representative has called her closest allies and senior legislators to help judge whether there is enough momentum to successfully impeach the president.

At least 143 of the 235 House Democrats believe the president should face impeachment proceedings, according to The New York Times.

Everyone Trump has fired or forced out Show all 13 1 /13 Everyone Trump has fired or forced out Everyone Trump has fired or forced out John Bolton Trump claimed to have fired Bolton, his national security adviser, while Bolton claimed he offered to resign. An anonymous White House source that Bolton's departure came as a result of the national security adviser working too independently of the president AFP/Getty Everyone Trump has fired or forced out Anthony Scaramucci Scaramucci lasted only six days in his role as Trump's communications director before being fired by John Kelly, the incoming chief of staff Getty Everyone Trump has fired or forced out Rick Perry Rick Perry announced his resignation just as he became embroiled in the president's impeachment scandal. The White House said Mr Perry was asked by Donald Trump to work with Rudy GIuliani in regards to Ukraine. AP Everyone Trump has fired or forced out Rex Tillerson Tillerson, Trump's first secretary of state, was fired after a series of clashes with the president over policy Getty Everyone Trump has fired or forced out James Mattis Mattis served as secretary of defense from the beginning of Trump's administration until retiring on 1 January 2019. However, the president later claimed that he had "essentially fired" Mattis Getty Everyone Trump has fired or forced out James Comey Comey was fired as director of the FBI early in Trump's presidency after serving in the role for four years prior. His dismissal is widely thought to have been related to the Russia investigation Getty Everyone Trump has fired or forced out Reince Priebus Priebus, Trump's first chief of staff, was forced out after six tumultuous months AFP/Getty Everyone Trump has fired or forced out David Shulkin Veterans affairs secretary Shulkin claims that he was fired, the White House claims that he resigned Getty Everyone Trump has fired or forced out John Kelly Kelly, Trump's second chief of staff, was forced out after 17 months in office. His departure was a confused affair though it is clear that Trump wanted Kelly out AFP/Getty Everyone Trump has fired or forced out Michael Flynn Flynn lasted 24 days as Trump's national security adviser before being fired for lying to the FBI Getty Everyone Trump has fired or forced out Lee Cisna Cisna served as director of citizen and immigration services between October 2017 and June 2019 before being asked to resign amid a major personnel change in the department of homeland security Everyone Trump has fired or forced out Madeline Westerhout Westerhout served as Trump's personal assistant after leaking private information about his family AFP/Getty Everyone Trump has fired or forced out Mira Ricardel Ricardel was forced out of her role as Deputy National Security Advisor after first lady Melania Trump publicly called for her to be fired

Mr Trump’s latest troubles began after an intelligence official filed a formal whistleblower complaint on 12 August, alleging the president’s conversations with a foreign leader were a matter of “urgent concern”.

The White House has refused to pass the complaint on to Congress, despite the fact that disclosure is required by the Intelligence Community Whistleblower Protection Act 1998.

Ms Pelosi has given Joseph Maguire, the acting director of national intelligence, until Thursday to hand over the complaint.

On Monday night seven House Democrats announced their support for impeaching the president, in an opinion piece for The Washington Post.

“We believe these actions represent an impeachable offence,” said the group, made up of politicians with past careers in the US military, defence and intelligence industries.

“We have devoted our lives to the service and security of our country, and throughout our careers, we have sworn oaths to defend the constitution of the United States many times over.”

“He allegedly sought to use the very security assistance dollars appropriated by Congress to create stability in the world, to help root out corruption and to protect our national security interests, for his own personal gain,” the group wrote.

“These allegations are stunning, both in the national security threat they pose and the potential corruption they represent.”

Democratic leadership aides told The Washington Post they believed an impeachment process was almost inevitable.

Individual representatives, such as Brad Sherman, have previously filed impeachment articles but these failed at the voting stage.

If Nancy Pelosi and the Democratic leadership choose to support the process, the president would likely face hearings.

Media reports in the US suggest the whistleblower complaint concerns a phone call between Donald Trump and Volodymyr Zelensky, the president of Ukraine.

The reports suggest the president pressured Kiev to launch an investigation into Hunter Biden, the son of Joe Biden, a 2020 Democratic presidential candidate and a former vice president.

Mr Trump is alleged to have asked Mr Zelensky eight separate times to launch a probe.

Hunter Biden previously sat on the board of Burisma, a Ukranian gas company.

The Trump administration put a hold on nearly $400m (£322m) US military aid to Ukraine a week before the call, according to CNN.

Mr Trump has denied he offered military aid to Kiev only if the country launched a probe into Hunter Biden.

“Imagine if the Mueller report had included evidence of a phone call between Trump and Putin in which Trump asked Putin 8 times for his help in the 2016 election,” said Robert Reich, a former Clinton administration official.

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“That would have been the smoking gun.”

If at least one article of impeachment is tabled in the House of Representatives and wins a majority of members’ votes, the president is technically impeached.

The issue then moves to the senate which conducts a trial, presided over by the Supreme Court’s chief justice.

If two-thirds of senators find the president guilty, he is removed and the vice president becomes president.

This outcome remains unlikely, as the Republican Party controls the senate.