Speaking on the BBC’s Andrew Marr Show, Hammond said that if Johnson is elected, as polling suggests, he would expect his cabinet members to accept a no-deal Brexit which is “not something I could ever sign up to”.
“It’s very important that a prime minster is able to have a chancellor who is closely aligned with him in terms of policy, and I therefore intend to resign to Theresa May before she goes to the palace to tender her own resignation on Wednesday,” he explained.
When asked what will happen in the event that Jeremy Hunt is appointed, Hammond said that this would complicate matters due to his “more nuanced” position.
“I haven’t heard him express clearly a requirement for a sort of loyalty pledge around the 31 October no-deal exit,” Hammond said.
Hammond said that even though all indications are that Johnson will take the position, and he has made his plans accordingly, he would wait until Tuesday “to see for sure”.
The chancellor would not be drawn on who he voted for in the conservative leadership contest, but said that this recent decision was “nothing personal” and that he actually found Johnson a “very engaging character”.
Hammond said, “Beyond the Brexit question, I don’t have major policy disagreements, he’s a middle of the road conservative, a liberal conservative I’d say. It’s simply a disagreement on Brexit policy and I cannot accept the idea of leaving with no deal on 31 October.”
He explained that he would support either candidate “so long as they’re genuinely pursuing a deal,” however he thought that a deal by 31 October was not possible due to a range of circumstances.
Earlier this month, the chancellor put the brakes on planned spending review in the autumn, saying it was up to the next government to decide if this was appropriate.
He also took the opportunity to challenge both the prime ministerial candidates’ spending positions saying, “The 'fiscal firepower' we have built up in case of a no-deal Brexit will only be available for extra spending if we leave with an orderly transition.
"If not, it will all be needed to plug the hole a no-deal Brexit will make in the public finances.”