Toby Flood said England's failure to score tries in their 19-9 defeat to Wales on Saturday was "embarrassing" and "shameful".
Although England's backs enjoyed plenty of possession and territory at the Millennium Stadium, they failed to make it pay with the Leicester fly-half brutally honest in his assessment.
Wales were forced to make almost twice as many tackles but England's attempts to bulldoze their way over the line were too predictable.
Nick Easter, the Harlequins number eight, admitted England "were not smart enough" in possession.
James Hook then showed England how to do it - the Wales full-back scoring the only try of the match and kicking two late penalties to seal victory.
England manager Martin Johnson was furious and Flood said: "I don't want to use the word embarrassing - but it is a little bit embarrassing.
"It hurts, the fact we couldn't score a try. It is shameful. We can use harsh words because if you want to win a World Cup, tries are massive."
England turned down penalty shots at goal and Flood did not attempt a single drop goal, which would at least have been some reward for their dominance and kept the scoreboard ticking over.
Jonny Wilkinson had done just that at Twickenham the previous weekend in England's 23-19 victory over Wales.
But Flood revealed England had a deliberate plan in Cardiff to put into practice some of the moves they have been working during their seven-week training camp.
It did not work, though, and the fact that none of the team's senior leaders recognised the need for a change of tactics during the match must now be a serious concern for Johnson.
"We could have gone out there and stretched the lead and kicked goals but we made the decision to go out there and see if things were working," said Flood.
"I am not too fazed about the result. It is insignificant compared to the fact we haven't been able to score a try.
"That is the hardest thing for me. That left us in a position where we think there is a lot of work to do over the next two weeks.
"We turned the ball over too much in the red zone. We won't get that many opportunities in the World Cup. We have got to be more clinical there.
"There are a lot of things to work on, a lot of food for thought.
"We are really disappointed and frustrated."
England have next week off before Johnson confirms his final 30-man World Cup squad on August 22, five days before their last warm-up international against Ireland in Dublin.
England's opening World Cup match is against Argentina in Dunedin on September 10.