Insults such as "opportunist", "inconsistent" and "dinosaur" were traded in the politest possible way as the two contenders for the Tory leadership faced one another for the final televised confrontation of the leadership campaign.
David Cameron, the 39-year-old shadow Education Secretary who looks increasingly like the winner, claimed to stand for "constructive opposition", not "opportunistic opposition", while Mr Davis described himself as "principled".
Aides admitted afterwards that the exchange, which took up an hour of lunchtime television, added very little to what was already known, as the candidates restated policy positions they have defended time and again during the campaign. Mr Davis's supporters claimed that he had emerged as the clear winner through "resilience, experience and a set of policies".
They claimed that Mr Cameron was out of line with public opinion when he argued that cannabis and ecstasy should be classified differently from harder drugs such as heroin, in order that government and police could give young people a message about drugs that they would find "credible". The shadow Home Secretary countered: "The first message about why ecstasy and heroin or cocaine are in the same category is that they all kill".
But Mr Cameron's advisers said that audience reaction overall showed that their man was the obvious winner, particularly in the arguments over tax and political strategy.
If Tony Blair was watching, he may have been heartened to know if David Cameron wins, the Government will have an ally in its battle with the Labour left over education reforms.
Mr Cameron said: "If the reforms give schools some extra autonomy, I want the Conservative Party to back that because I want us to be a principled party."
But Mr Davis, who played a key role in engineering Tony Blair's recent Commons defeat on the Terrorism Bill, warned that there would be an "argument" if Mr Cameron insisted on backing the Government.
"You talk about consistency David, but before the election you supported our policy on immigration, on tuition fees, on health care. You changed your mind on the back of a single election loss."
Mr Cameron said: "The Conservative Party has got to look at the fact not that we lost one election but that we lost three. If we don't make changes we will lose again."