- Video report by ITV News National Editor Allegra Stratton
Tracey Crouch has said she has "absolutely no regrets" about her decision to resign in protest at a delay in introducing a cut to the maximum stake for fixed-odds betting terminals (FOBTs).
The former sports minister's action drew applause from across the political spectrum and won praise from the Archbishop of Canterbury Justin Welby.
Meanwhile questions were raised over why Theresa May allowed Ms Crouch to resign over the issue.
Sources told ITV News Political Correspondent Paul Brand it was "a complete own-goal and the PM should have budged".
The MP resigned from her ministerial post after insisting that not cutting the maximum wager on FOBTs from £100 to £2 until October 2019 was "unjustifiable" and indicated it could cost lives.
The move appeared to energise support for bringing in a bet limit earlier, with talk of Mrs May facing a potential rebel amendment to the Finance Bill later this month.
Asked about her resignation on Friday morning, Ms Crouch said: "I have absolutely no regrets about my decision whatsoever, I'm perfectly comfortable with my decision."
She added that she was looking forward to "being a supportive member of the backbenches".
There was support for Ms Crouch's stance from all sides of the Commons.
Labour's Deputy Leader Tom Watson said her resignation had "caused fury" on both sides of the House of Commons.
"We think she goes with her integrity intact but we're very disappointed because we wanted to implement the policy that she developed," Mr Watson said.
"If any good comes out of the resignation of a well-respected minister it will be that finally the Government will recognise that there is a majority in the House for changes and that might mean we can bring those reforms forward again so that they're not delayed and there's not more misery caused in the gambling sector."
Former foreign secretary Boris Johnson, International Development Secretary Penny Mordaunt and Commons Leader Andrea Leadsom were also among those to speak warmly about Ms Crouch after she quit.
The Archbishop of Canterbury Justin Welby tweeted that Ms Crouch was "principled and courageous" for resigning over the issue.
Ms Crouch had been a leading campaigner in reducing the maximum stake for FOBTs.
In a hard-hitting resignation letter to the prime minister, Ms Crouch said: "Unfortunately, implementation of these changes are now being delayed until October 2019 due to commitments made by others to those with registered interests.
"From the time of the announcement to reduce stakes and its implementation, over #1.6 billion will be lost on these machines.
"In addition, two people will tragically take their lives every day due to gambling-related problems and, for that reason as much as any other, I believe this delay is unjustifiable."
Mrs May replied that she was "disappointed" by Ms Crouch's move and insisted there had been no delay.
She wrote: "There has been no delay in bringing forward this important measure.
"Indeed, as you know from your work as the minister responsible, we listened to those who wanted it to come into effect sooner than April 2020 and have agreed that the changes should be in place within the year - October 2019.
"Having taken the decision to make this very significant cut in maximum stakes, we must ensure that this change can be implemented in an orderly and effective manner to make sure it delivers on the results we all want to see."
Mrs May did not immediately replace Ms Crouch as sports minister and is believed to be considering candidates for the role.