He also faced significant criticism for keeping his SNP (Scottish National Party) office open to the public during the COVID-19 pandemic lockdown, and for comments describing the Irish Republican Army as "freedom fighters".
He was the SNP's longest-serving Glasgow councillor, and during his term, he led many protests against Labour's moves to weaken effective opposition by altering the council committee system.
[4] On 30 June 2008, David Marshall, Labour MP for Glasgow East, resigned from the UK Parliament on the grounds of ill-health,[5][6] thereby triggering a by-election.
[11] Mason won the by-election in a surprise victory, defeating the Labour candidate Margaret Curran, MSP for Glasgow Baillieston.
"[21] Journalist and sketchwriter Alex Massie described him as, "the well-meaning creationist SNP member for Glasgow East... Mr Mason is a Holyrood treasure, a great entertainer in the long tradition of impressively bumbling backbenchers who add to the gaiety of parliamentary proceedings.
The Bible’s teaching is that a follower of Jesus should not have a sexual relationship with someone of the same sex.”[24][25] In 2020 Mason returned to the question of gay sex, informing the Scottish Parliament whilst debating the Hate Crime Bill that the legislation would mean, "[Green party co-leader] Patrick Harvie and I can continue to debate who should or should not have sex with whom... That is a sign of a healthy society and a healthy democracy.
[25] In January 2015 he spoke in parliament in favour of teaching school children young Earth creationism, claiming that it cannot be "disproved by science".
"[30][31] In February 2017, The First Minister of Scotland, Nicola Sturgeon apologised to the families of three Scottish IRA murder victims after Mason had claimed members of the terrorist organisation could be considered freedom fighters.
[35][22] In May 2018, Mason was criticised for comparing the child sexual abuse by former Celtic Boys Club employees to tax avoidance schemes.
[38] In June 2018 Mason responded to an email from a constituent that he did not agree with retrospective pardons for gay men convicted of having consensual sex before decriminalisation.
[40] In March 2020, he came under criticism for refusing to follow Scottish Government advice and keeping his parliamentary office open to the public during the COVID-19 pandemic.
"[43] In 2021, amid reports of a cleansing and vermin crisis in Glasgow, Labour MSP Pam Duncan-Glancy told Holyrood that there were even rats in her flat.
[46] In September 2022 it was reported that Mason was disciplined by the SNP for defending the anti-abortion protests and "causing distress and trauma to women in the way he expressed his views on abortion rights" [47] In January 2022 Mason referred to trans women as "people whose biological sex is male" and suggested that those convicted of crimes should serve their sentences in male prisons.
[49] In June 2022, Mason told a constituent that he was "pretty positive" about the overruling of Roe v. Wade and the end of US-wide abortion rights.
In response Scottish Government Minister for Women's Health, Maree Todd MSP wrote, "For the avoidance of doubt: There is nothing positive about the recent US court ruling.
He had tabled a motion in parliament welcoming the proposal but called for "more equality for all unborn babies in the future” and compared miscarriage and premature death to abortion.
Lennon said “Anti-choice campaigners will take every opportunity to undermine abortion rights, and this parliamentary motion from the SNP’s John Mason is the latest example.
[55] The legislation Mason is referring to is Gillian Mackay's private members bill to introduce safe access zones around hospitals and clinics providing abortion services In August 2024, Mason had the SNP whip suspended after claiming that if Israel wanted to commit genocide in the wake of October 7th, it would have killed ten times as many civilians.