Boris Johnson made his first public comments since the burka row erupted on Sunday but refused to address questions as he greeted the media armed with a tray of mugs.
"I have nothing to say about this matter except to offer you some tea," he told the journalists camped outside his home in Oxfordshire.
The former foreign secretary returned from holiday in Italy amid outrage over his comments on the burka, of which his father has said were "spot on".
Stanley Johnson even suggested his son should have gone further and called for a ban on the face-covering garment in certain circumstances.
Writing in the Sunday Telegraph he said: "Surely, there are circumstances where a ban or appropriate restrictions would be in order."
Meanwhile, the Muslim Council of Britain, said Conservative MPs’ support for the ex-foreign secretary over his comments comparing Muslim women in burkas to bank robbers has “shone a light on the underbelly of Islamophobia” within the party.
Harun Khan, MCB secretary general, said Mr Johnson's claims last Monday - which are now subject to an investigation - had a “real and worrying” impact on the Muslim community.
He also said the MCB received Islamophobic hate mail off the back of the furore, some describing Muslims as “barbarians”.
Mr Khan’s comments came as the row continued to generate fierce debate within Tory party circles over Monday's Daily Telegraph newspaper article.
A former aide to David Cameron condemned Mr Johnson as "pathetic, weak and needy" as Tory MP Jacob Rees-Mogg defended him and condemned the investigation into his comments as a "show trial".
What else did Stanley Johnson say?
Just as his son did last Monday, Stanley Johnson has penned an article expressing his controversial personal opinion on the Islamic headgear.
Mr Johnson Snr is in full support of his son's comments and claims that in Somerset there is a "near-universal" agreement that the younger Johnson has done nothing wrong.
He said: "Yes, Boris used some colourful language. That's called 'freedom of speech' or it was in my day.
"As a matter of fact, I would have liked him to have gone a bit further."
The former I'm a Celebrity...Get Me Out of Here! contestant went on to question why Conservative politicians have spoken out against his son and suggested Labour would benefit from Tory infighting.
"Why the all furore? Why has this disastrous 'blue-on-blue' warfare broken out?
"The Chairman of the Conservative Party is setting up a Committee of Enquiry into whether Boris's use of the word 'letter box' breaches party rules."
He added: "If that isn't an own-goal, I don't know what is. Mr Corbyn must be rubbing his hands with glee."
The older Mr Johnson's article comes hours after Harun Khan claimed Islamophobia had been exposed in the Conservative Party.
How does Harun Khan justify his Tory party Islamophobia claim?
In a statement, Mr Khan said: “The impact of Boris Johnson’s comments are real and worrying and indicate the importance of a full, transparent and independent investigation into his conduct, in particular given the lack of action in previous cases of Islamophobia in the party.
“The comments and belief by a number of Conservative MPs that not even an apology is required has shone a light on the underbelly of Islamophobia that is present within the party – one that can only be tackled by sincerely changing course and positively responding to calls for an independent inquiry into Islamophobia in the party.”
How did David Cameron's former aide attack Mr Johnson?
Further condemnation came from Andrew Cooper, David Cameron’s former Downing Street aide, who pulled no punches with his assessment of Mr Johnson.
In a Twitter post, he wrote:
What do Mr Johnson or his supporters say?
Mr Johnson, who is holidaying abroad, is yet to respond to the furore sparked by his article on Monday.
His article, in which he opposed a ban on the burka or niqab, sparked outcry after he branded the face-covering veils “ridiculous” and “oppressive” and said Muslim women wearing them looked like letter-boxes or bank robbers.
There were further signs of grassroots Tory anger over the affair, with the Telegraph giving over its whole letters page to reaction from readers after being “inundated” with messages of support for Mr Johnson.
And it was reported that letters have been sent to the party complaining about chairman Brandon Lewis, whose demand for an apology from Mr Johnson provoked an escalation in the row earlier this week.
Why did Jacob Rees-Mogg say the investigation is a 'show trial'?
Mr Rees-Mogg suggested the attacks on Mr Johnson’s comment were a reflection of “envy” felt towards him because of “his many successes, popularity with voters and charisma”.
He said the party’s investigation into Mr Johnson had been set up as a “show trial” in a bid to derail any long-held ambitions the former Cabinet minister may have for Tory party leadership.
The howls of outrage directed at the former figurehead of the Leave campaign were “suspect” and the motivations of those attacking him “dubious”, said the North East Somerset MP.
“Could it be that there is a nervousness that a once and probably future leadership contender is becoming too popular and needs to be stopped?” asked Mr Rees-Mogg.
“This may explain the attempt to use the Conservative Party’s disciplinary procedures, but it has been handled so ham-fistedly that it brings only sympathy and support for Mr Johnson.”
And he added: “When Margaret Thatcher was leader, she and Michael Heseltine were hardly soulmates, but she would not have allowed personal rivalry to take the heat off the Labour Party, whose own deep internal divisions are buried in other news now, nor would she have countenanced any attempt to have a show trial.
“Attacking Boris merely helps the Opposition. It is time for good sense to assert itself, free speech to be encouraged and, as the summer rain falls, for hot-headed action to be cooled down.”
Who is investigating Mr Johnson?
Mr Johnson’s comments on the burka have been branded “inflammatory and divisive” by the Equality and Human Rights Commission, but the watchdog made clear it was not launching its own investigation.
A panel including one independent figure, one representative of the voluntary party and one nominated by the backbench 1922 Committee, will look into complaints that Mr Johnson’s comments breached the Conservative Party’s code of conduct.
Under party rules, the head of the panel may dismiss the complaints if they are found to be obviously trivial, lacking in merit or unable to be fairly investigated.
Disciplinary action could lead to Mr Johnson being suspended or even expelled from the Tories, but would risk igniting civil war in a party many of whose members see him as the best option to succeed Mrs May as leader.
But there have also been suggestions that he could be ordered to attend a diversity training course.