The band headlined the final evening of the three-day event, by which point the site was a mudbath after torrential rain.
Daltrey told The Sun: “We thought ‘Who the fuck’s going to be here after three days of horrendous weather?’ It was like Paschendaele.
“The conditions were horrendous and you think no one is going to stay to the end. It was like the 70s when the crowds got bigger.”
Daltrey has also spoken out about the fact their last album ’Endless Wire’ was not played on the radio.
The album was released in 2006 and was the rock legends’ first studio LP in 24 years.
Daltrey said: “We don’t even get played on Radio 2 and if they don’t play you, you don’t get heard.”