Boris Johnson, a frontrunner in the race to become the next British prime minister, ruled out a general election deal with the newly-formed Brexit Party in his final Conservative Party leadership debate on Wednesday.

The Conservative Party has been badly stung by the Brexit Party, which was launched earlier this year by veteran Eurosceptic Nigel Farage and stormed to the top place in the European Parliament elections.

Asked if he would work with the Brexit Party that has attracted thousands of followers from his Conservative Party, Johnson said: "I rule it out."

He said the Conservative Party should not do deals to keep Labour Party leader Jeremy Corbyn out of Downing Street.

Referring to the fact that hundreds of thousands of people voted for rival parties in recent elections, Johnson told the audience that "we are stirring down the barrel."