Last week, Hammond said that he would not serve under a prime minister who was prepared to leave the European Union without a deal, as proposed by former UK Foreign Secretary Boris Johnson and other contenders seeking to become Britain's next top political leader, Reuters reported.
Johnson said the UK should be prepared to leave the EU without a deal on 31 October and that withholding the nearly 50 billion euros ($56 billion) that May agreed last year to pay the EU could help London get a better deal, according to Reuters.
The United Kingdom was supposed to have left the EU in March but failed after parliament refused to back May's withdrawal agreement. London is now facing a 31 October deadline.
Amid the Brexit deadlock, May resigned earlier in June but will remain in a caretaker position at the post until a new Conservative Party leader is elected.
Last week, the UK Conservative Party held its first round of the party leadership elections. Johnson won the election with 114 votes, incumbent Foreign Secretary Jeremy Hunt came in second with 43, and the Secretary of State for Environment, Food and Rural Affairs, Michael Gove, was third with 37 votes. UK Secretary of State for Health and Social Care Matthew Hancock after gaining only 20 votes has left the race.
The next round of voting will be held on Wednesday-Thursday.