DAVID Cameron has admitted that voters might question his passion for his job because he is too smooth.

And, as the polls show no sign of the Tories opening up a winning lead, the Prime Minister vented his frustration, declaring: "I don't know what more I can do."

Speaking to the right-wing magazine The Spectator, the Conservative leader revealed how he struggled to understand why people on his own side questioned his will to win.

Speaking as he travelled to Yorkshire for campaign events, he said: "There is something about me - I always manage to portray a calm smoothness or something."

But he then pointed to his campaign schedule and said: "But look, yesterday, where was I? I went to five seats, I did five speeches, I didn't finish until way after the other party leaders were home having TV training or something.

"I was out on the stump and I'm doing the same today. Look at my schedule. I don't know what more I can do."

Mr Cameron admitted he found criticism of the way his government sold its message "frustrating" but vowed: "If I need to do more to communicate that, I will."

In an earlier interview with ITV's This Morning, Mr Cameron admitted the "close election" meant he was not getting to see his family as much as he would like, revealing his four-year-old-daughter often asked if he had won the election yet.

The PM admitted the race for power would be close all the way to May 7 and promised to give the campaign "everything I have got".

While, he explained, his family was sad it was not seeing as much of him as it wanted to but it was very enthusiastic.

"Even Florence gets there's a blue team and I'm in charge. She keeps coming back home at night and saying 'Daddy have you won the election yet?' (I say) 'No, no it doesn't work like that, it's a long process.'"

He added: "This is such an important election for our country so I'm going to give it everything I have got."