Philip Hammond has condemned the "terrifying" attitude to no deal of allies of Boris Johnson, as the pound plunged further against the dollar and the euro.
The chancellor condemned Jacob Rees-Mogg, a supporter of Mr Johnson, for claiming a disorderly Brexit would not hit the economy.
Ahead of the final hustings of the Conservative leadership contest, Theresa May appealed for compromise in politics rather than absolutism in a valedictory speech.
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Mr Johnson will not give a figure for his planned corporation tax cut.
Mr Johnson's tax cuts will stimulate economic growth and therefore pay for his planned spending commitments, he tells a questioner.
In contrast, Jeremy Corbyn, wants to "pluck the feathers" of some "beautiful" metaphorical economic bird to the extent that the UK would enter a "death spiral", he says.
What would Mr Johnson do to teach children to manage money?
"Clearly we are not doing enough," he says. "Of course, the answer is better education in both primary and secondary."
Mr Johnson adds that he plans to boost schools funding. He pledges to consider specifically with a future education secretary the point the questioner raised.
"Are you good at managing money?" asks Mr Dale.
"I've certainly spent a lot," says Mr Johnson.
Would Boris Johnson work with the Brexit Party to prevent Jeremy Corbyn entering No 10?
"I don't believe that we should do deals with any party," says Mr Johnson.
"I rule it out," he adds in response to a shouted intervention.
A questioner asks Mr Johnson whether a fresh general election is essential for the new PM.
The frontrunner suggests that Britons are weary of elections and referenda; rather than holding an election the Tories should push through Brexit, he says.
Mr Johnson strenuously denies the "outrageous suggestion" that he dyes his hair.
Such questioning, apparently at the behest of newspaper journalists, shows how long a campaign this has been, he says.
He is now speaking about work he did at the Foreign Office to promote girls' education around the world. He describes it as a "Swiss army knife policy" to insist on the improvement of schooling for girls.
Mr Johnson "absolutely" describes himself as a feminist, meaning someone who believes in the "equality of human beings", he says.
He is "not certain that introducing quotas" - ie all-female shortlists for parliamentary constituencies - is a good idea, though.
"I think the whole withdrawal agreement is effectively defunct," Mr Johnson says, but the backstop is the worst bit.
Mr Johnson says he doesn't believe the backstop would work.
Pressed further on the willingness of Brussels to budge on the negotiations, Mr Johnson cites the readiness of European governments to expel Russian spies from their countries in the wake of the Salisbury poisonings.
And if Mr Barnier will not compromise, "we have to get ready to come out on different terms".
Mr Dale brings up Michel Barnier's statements that the withdrawal agreement cannot be re-negotiated.
Mr Johnson constructs an answer around a different part of the preamble to the operative point, when Mr Dale mentioned plans for a European army.
On the prospect of proroguing parliament, Mr Johnson says he believes MPs are now "psychologically ready" to deliver Brexit.
The Tories in particular are "staring down the barrel", he says.
Mr Johnson will not say when he would introduce a Queen's speech. "Our priority is to get Brexit done on 31 October", he says.
Mr Johnson, in keeping with recent custom, has spoken a great deal about his time as the mayor of London but not at all about his time as foreign secretary.
It came, he says, from a kipper-smoker who has been forced to include ice-packs with his shipments. The move by the old enemy - "Brussels bureaucrats" - has sent his costs soaring, Mr Johnson says.
"We need to get our mojo back as a party," says Mr Johnson. Now he is holding up a vacuum-packed fish. A kipper, apparently.
And the spectre of Mr Corbyn rises over the Excel centre once again. The Labour leader's "economic programme would be catastrophic for this country", Mr Johnson claims.
He's even tried speaking Spanish, during a comparison of our Iberian neighbours' apparently blistering internet speeds compared to our own.
And at high volume, it might be added.
Mr Johnson has started at full pelt, whizzing through promises for the future and reminiscences about his past successes.
