Simon Carr: Lots of quick answers. But the questions keep on coming

Sketch: But what big, blue eyes Cameron has! Did you know he has such blue eyes?

The leader of the Conservative Party sat in a TV studio at Stourbridge in the West Midlands with a group of 20-odd ethnically balanced, demographically weighted undecideds. Retired engineer, unemployed engineer, businessman, Kashmiri nurse, single mother. They were probably all voters, and that made them unusual.

Could the Tory win them over? What did he have for them?

Many interesting questions got fast, fluent replies. His words tumbled out with sincerity and intelligence. And to his allies and advisers, they may have formed a fine description of Conservative thinking.

But what big, blue eyes Cameron has! Did you know he has such blue eyes? If I was a voter I'd be left with that single piece of information, perhaps. That, and an impression of "too many notes". There is much to be said, but with so much at such pace, not as much goes in as he hopes.

Most of the interesting answers were being saved for the campaign. And some may not have had their finishing touches. The host asked about their plan to recognise marriage in the tax system.

"You were saying you wanted to do this five years ago, and we still don't know what it means. Why does it take five years to work out!"

That was more a yelp than a question. The true answer is short (consisting of the two words "Oliver Letwin" as he's in charge of policy development). Cameron let his eyes shimmer a little, by way of reply.

What else? He was still going to allow tens of thousands of immigrants to come in. Three questions from one man. 1) Where would they be housed? 2) Who will employ them? And 3) With our debt levels who will pay their benefits?

This is a question that resonates through the undecideds. It needs an answer that doesn't use the phrase "building a strong economy". Mind you, imagine the database of knowledge you'd need to carry round in your head to start the answer.

Then the Muslim nurse, Somia Kausar, rather tripped him with a question asking whether money paid on immigrant patients would be better spent training local doctors.

Paul Bennett gave us some moving testimony. "You talk about 'transformational change'. I was born to a shop steward and brought up on one of the toughest estates, now I'm a partner in a law firm. My transformational experience was a grammar school." It got an interesting answer from Cameron that probably failed to satisfy his interrogator. Re-fighting the grammar school battle "wasn't a good use of time and effort. It's an argument that's passed," Dave insisted. The answer was to open up the state sector with freedom and competition. That was one part when he came alive, to bash Remley Mann – she said collaboration not competition was the source of academic achievement. "I disagree," he said cheerfully. "This sometimes happens, there's no point in trying to soft-soap you – I profoundly disagree."

Is he too posh? He was asked, "How can people relate to you if you come from a privileged background?" This is a recurrent question. It features in polling. It's a decider. He said listening was important. There is surely a better answer – about how culture, manners, civic affection, patriotism, personal interest and sympathy, shared values and virtues, a fundamental recognition of human equality – how these things can, should and must transcend class. Actually, it's a message at the foundation of conservatism – which may be why the structure is a little shaky just now.

Were the audience persuaded, wooed, repelled? It may depend on whether they like blue eyes.