A former British spy who was an FBI source in its probe of Donald Trump’s presidential campaign had a lengthy friendship with Ivanka Trump, the president’s daughter, a source familiar with the friendship says.

A friendship between Christopher Steele, a former officer of British foreign intelligence agency MI6, and an unspecified Trump family member was laid out in a report by the US Justice Department’s Inspector General published today.

The report looked into elements of how the FBI handled its investigation into whether Donald Trump’s 2016 presidential campaign had colluded with Russia.

The FBI used Mr Steele’s work as part of its investigation.

The report found numerous errors but no evidence of political bias by the FBI when it opened an investigation into contacts between Mr Trump’s presidential campaign and Russia in 2016.

Mr Trump has harshly criticised the FBI probe as biased.

The report by Inspector General Michael Horowitz gave ammunition to both Mr Trump’s supporters and his Democratic critics in the debate about the legitimacy of an investigation that has clouded the first two years of his presidency.

Michael Horowitz , Inspector General, Department of Justice,

The new report by Inspector General Michael Horowitz is not expected to be the last word on the FBI probe of Donald Trump’s campaign to be US president. Photo: AFP

In a chapter of the report reviewing the history of Mr Steele’s relationship with the FBI as a “confidential human source,” Mr Steele said that allegations that he was biased against Mr Trump from the start of his investigation into the presidential candidate were “ridiculous”.

According to the Inspector General’s account, Mr Steele told investigators that, if anything, he was “favourably disposed” towards the Trump family, since he had visited a Trump family member at New York’s Trump Tower and “been friendly” with the family member for “some years”.

Mr Steele added that he once provided that person with a gift in the form of a Steele family tartan from Scotland.

A person familiar with the friendship told ABC News that Ivanka Trump was the unnamed family member mentioned in the report.

The White House declined comment and Mr Steele did not respond to an email requesting comment.

17 basic FBI errors detailed

The FBI investigation, opened in the summer of 2016 ahead of the November election pitting Mr Trump against Democratic candidate Hillary Clinton, was taken over in May 2017 by former FBI chief Robert Mueller.

Mr Mueller’s 22-month special counsel investigation detailed a Russian campaign of hacking and propaganda to sow discord in the United States, harm Mrs Clinton and boost Mr Trump. Mr Mueller documented numerous contacts between Trump campaign figures and Moscow but found insufficient evidence of a criminal conspiracy.

It will not be the last word on the subject.

Federal prosecutor John Durham, who is running a separate criminal investigation on the origins of the Russia probe, said he did not agree with some of the report’s conclusions.

Attorney General William Barr, who ordered the Durham investigation, said the report showed that the FBI launched its investigation “on the thinnest of suspicions”.

Former foreign policy adviser to Donald Trump Carter Page.

Carter Page Photo: AFP

Mr Horowitz found that the FBI had a legal “authorised purpose” to ask for court approval to begin surveillance of Carter Page, a former Trump campaign adviser.

But Mr Horowitz also found a total of 17 “basic and fundamental” errors and omissions in the original application and all subsequent renewals to the Foreign Intelligence Surveillance Court (FISA). Those errors made the case appear stronger than it was, Mr Horowitz said.

In particular, the report singled out an FBI lawyer who altered an email contained in a renewal of the application which claimed that Mr Page was “not a source” to another US government agency.

In truth, Mr Page served from 2008 to 2013 as a “operational contact” to another agency, which was not identified in the report.

The lawyer was previously identified by Republican Representative Mark Meadows as Kevin Clinesmith, who is no longer with the agency. Mr Clinesmith, former FBI attorney Lisa Page and former special agent Peter Strzok were among a group of FBI employees found by Mr Horowitz last year to have exchanged text messages critical of Trump.

Mr Clinesmith did not immediately respond to a request for comment.

“This was an attempted overthrow and a lot of people were in on it, and they got caught,” Mr Trump told reporters at the White House in reaction to today’s report.

– Reuters