John Bercow, the Commons Speaker, strongly criticised the tech giant after being told it had broken a promise to take down extremist material from YouTube.
He suggested the Commons Home Affairs Select Committee should haul Google bosses back before it – or make an application to him alleging “contempt of the House”.
“That is a recourse open to her if people do not comply and do not honour their undertakings,” he told Yvette Cooper, the committee’s chair.
The Labour MP had protested that the National Action video remained available online, despite Google repeatedly promising it would be taken down and take steps to prevent it reappearing.
“This is one of the richest companies in the world and it is failing to meet its basic responsibilities to tackle extremism and protect public safety in this country,” Ms Cooper told MPs.
In response, Mr Bercow branded National Action a “despicable, fascist, neo-Nazi organisation” and told MPs: “If those commitments have been made, they must be honoured.”
The four-and-a-half minute propaganda video at the centre of the controversy was removed within hours of his warning, but the uploader had called on viewers to “preserve” the footage by re-uploading it in other forms.
It features a National Action demonstration in Darlington, which took place a month before the group was banned, showing members marching through the streets with the group’s black flag and performing Nazi salutes.
A leader is seen using a loudhailer to claim that white British people will become a “despised and persecuted minority”.
“We are preparing for the fight of our lives…will take back what is rightfully ours, by birth and by the will of God,” he says.
“National socialists will rise once more, we will finally win back our lands and win back our continent and then our race will forever be free.”
The video includes antisemitic slurs, racism and wide-ranging incitement to violence against politicians, celebrities and the “upper class”.
The Home Affairs Committee has accused YouTube of “either incompetence or unwillingness to act”, after being asked at least eight times in a year to take down the footage.
In a statement to The Independent, a spokesperson blamed a technical failure for it remaining online, but insisted it was “getting faster at removing violent extremist content”.
“We don’t allow National Action to have a channel on YouTube and we remove National Action content that’s uploaded by third parties,” the spokesperson said.
“Our systems haven’t worked 100 per cent in this instance, and we apologise for that. We’re getting faster at removing violent extremist content by investing in machine learning technology and by hiring more people.”
Ms Cooper said the response was “just not good enough”.
“It is beyond belief that this illegal, white supremacist video is still available on YouTube,” she told The Independent.
“It is disgraceful that it takes a parliamentary committee to make one of the richest companies in the world take action against propaganda supporting a proscribed terrorist group.
“The fact that YouTube are doing nothing to proactively search for this extremist content, despite repeated assurances to me and the committee, shows they are not taking the problem anywhere seriously enough.
“They made commitments to Parliament to tackle this and they have repeatedly failed to do so even though they have the resources, the technology and the staff to do it.”
Ms Cooper called for the Government to bring in fines for companies that fail to take proactive action against extremist material, like those implemented in Germany.
Amber Rudd, the Home Secretary, said she would work with the Labour MP to ensure Google and other firms are “held to account”.
“The fact is that internet companies have made good progress at taking down Isis-focused material,” she told MPs. “But we need to see much more effort into the particular area of the extreme right-wing groups.”
The debate came after security services revealed that 10 Islamist and four far-right terror plots had been foiled in the past year.
Mark Rowley, the outgoing head of national counter-terror policing, made the figure public for the first time to “illustrate the growth of right-wing terrorism”.
“The right-wing terrorist threat is more significant and more challenging than perhaps the public debate gives it credit for,” he warned last week.
Mr Rowley said there was “no doubt” that the Finsbury Park attacker had been radicalised by far-right material posted online by the likes of Tommy Robinson and Britain First.
Robinson, whose real name is Stephen Lennon, was recently handed a temporary ban by Twitter and Britain First leaders were banned from the social network long before being jailed for hate crimes on Wednesday.
But both Robinson and Britain First retain large followings on Facebook and YouTube, where their videos and speeches are widely available because they do not contravene current laws.
The Government recently unveiled free artificial intelligence technology that can identify Isis propaganda videos and prevent them being uploaded with a 94 per cent success rate.
But the identifiers used are not present in footage created by other terrorist groups, leaving tech firms to rely on wider-ranging filters, human moderators and flagging by viewers.
National Action was proscribed as a terrorist group in December 2016, when the Government called it “a racist, anti-Semitic, and homophobic organisation which stirs up hatred, glorifies violence, and promotes a vile ideology”.
Members glorified Thomas Mair, who murdered Labour MP Jo Cox, and took on his slogan “death to traitors, freedom for Britain” after he shouted it in court.
Several alleged members have been arrested in waves of police operations across the country, including men accused of planning to murder a Labour MP with a machete and serving British Army soldiers.
After The Independent reported that National Action members were trying to evade proscription by splitting into regional groups and operating under new names, its aliases Scottish Dawn and NS131 were also banned, but other factions are believed to remain active.