MPs on the Public Administration Select Committee yesterday questioned Shawcross as part of a pre-appointment hearing to assess his suitability for the role of commission chair.
The committee voted in favour of Shawcross being appointed by four votes to three and its report on his suitability is due to be published this afternoon.
But the Liberal Democrat MP Greg Mulholland – who, along with the Labour MPs Paul Flynn and David Heyes, voted against Shawcross being appointed – said the views he had expressed in the past, such as supporting the Iraq war and urging people to vote Conservative, made his appointment impossible.
"Mr Shawcross is a well-respected but controversial journalist and has written articles, all on his website, defending Rupert Murdoch and Guantanamo Bay and expressing his support for the Iraq war as well as attacking the previous government," said Mulholland in a statement. "He is, of course, entitled to express all those views as a journalist, but to then seek to also be the chair of the Charity Commission is just not tenable.
"He has also in his writings publicly espoused not only a clear party political preference, to the Conservative Party, but has also been quite disdainful of other political parties, something that will make it difficult or impossible for him to command the necessary confidence of the many people in the Liberal Democrats and Labour parties who work with and for charities."
Mulholland pointed to an article written by Shawcross and published on the American conservative website National Review Online before the UK general election in 2010, in which he said: "The disaster we face now is thanks uniquely to Gordon Brown and the Labour Party’s postmodern authoritarianism. A vote for the Lib Dems helps Brown: it could even keep him in power. Only a vote for the Conservatives offers any hope of drawing back from the abyss."
Mulholland said: "Dame Suzi Leather was dogged unfairly throughout her successful years in office by her membership of the Labour Party, but she never made any provocative or controversial political comments, the way Mr Shawcross has on a regular basis, as he would as a political commentator.
Mulholland said it was a mistake on the part of the Cabinet Office to suggest Shawcross for the role and the department would be "subject to accusations of political bias in doing so".
Heyes said that Shawcross’s well-established political views made him unsuited to the role of chair.
"The advert for the Charity Commission job makes clear the need to be impartial and independent and says that involvement in significant political activities would represent a conflict of interest," he told Third Sector. "Shawcross has problems in this respect and he should not have been put forward."
Bernard Jenkin, the Conservative chair of the committee, told Third Sector that holding political views did not mean it was impossible to make judgements and act impartially, something that Leather herself had pointed out.
"The committee has confirmed his appointment and there is every reason to have confidence in that judgement," he said. "I do hope that people will judge him for how he performs as chair of the Charity Commission, rather than assuming he is somehow disqualified for views he has previously expressed."
Jenkin said he did not use his casting vote as committee chair.