The rebels included 17 former ministers, who backed Yvette Cooper's amendment while warning the Prime Minister that the defeat by seven votes was merely an "opening salvo" in the battle to prevent a no-deal Brexit.
Among them were Sir Michael Fallon, Kenneth Clarke, Justine Greening, Nicky Morgan, Sir Oliver Letwin and Dominic Grieve.
But supporters said the vote - of 303 to 296 - showed there was now a clear majority of MPs who would oppose a no-deal if Mrs May can not, as many expect, win the backing of the Commons for her agreement.
So if May comes back with an alternative plan, that plan can be amended by MPs, opening up a range of possibilities for parliament to set the direction.
That would allow time for either new elections or a second referendum that would let the public finally break this deadlock.
Ahead of the visit, he said: "The Government is spending plenty of taxpayers money preparing for a no-deal Brexit but it's very clear it is not taking seriously the disruption that would take place".
There will be five days of discussion on the terms of the UK's withdrawal and future relations with the European Union ahead of an expected vote next Tuesday.
James's words appeared to represent the starkest threat yet to Tory MPs that if they fail to back the PM then they risk losing Brexit itself.
"The deal that is on the table is the best and the only deal possible", European Commission spokesman Margaritis Schinas said in Brussels, adding that the bloc is "closely" watching Brexit developments in the U.K. Commission President Jean-Claude Juncker plans to speak to May again this week. A day later, Varadkar addressed members of Bavaria's ruling Christian Social Union party, and told reporters afterward he shares with Merkel a "strong desire" to aid May as she faces defeat in next week's vote.
The former cabinet office minister, in charge of civil resilience, was withering about the no-deal planning he advocated.
"Todayâs trial can not possibly duplicate the reality of 4,000 trucks being held at Manston airport in the event of a no-deal Brexit", the RHA's chief executive Richard Burnett said in a statement.
"We don't want to trap the United Kingdom into anything - we want to get on to the talks about the future relationship right away".
"But there's little point in extending if all we are going to do is seek another tweak or twiddle to the Withdrawal Agreement".
Ex minister Nick Boles revealed today he had received a death threat for the first time after joining a Tory revolt against no deal Brexit.
And she said: "More than ever we need to find the centre, reach across the House and find a majority for what will be agreed".
The Irish backstop negotiations have been the single most intractable issue and some have suggested that reassurances on the Irish backstop were likely to include proposals to minimize any regulatory differences between Northern Ireland and the rest of the UK.