YouGov - Cameron competent but lightweight
YouGov's monthly poll for the Telegraph has topline voting intention figures, with changes from the last YouGov poll, of CON 45%(-2), LAB 26%(+1), LDEM 17%(+1). There is also a slight improvement in Brown's ratings as PM and on the forced choice question, but they remain dire - this is really another no change poll.
The poll was conducted between the 23rd and 25th July and the nature of YouGov's fieldwork means the majority of responses come on the first day, so almost all of the fieldwork would have been done prior to the Glasgow East result and the resultant press coverage.
YouGov also asked a series of questions about how David Cameron is seen. While questions in recent polls show Gordon Brown is viewed negatively across the board, there are still far more nuanced views of David Cameron. In some areas his public impage is unambiguously good - 57% think he is likeable (22% think the opposite), 52% think his is caring (22% uncaring), 51% think he is competent (19% incompetent), 45% think he is decisive (28% indecisive). There are still negative marks on his image though. He is still viewed as a lightweight by 50% of people, inexperienced by 57%, not in touch with ordinary people by 44%, somewhat shallow by 39%.
How much this matters at the moment is a different question. Cameron has a huge lead in best Prime Minister questions when put aside Gordon Brown (37% to 18% in this poll), and the details of Independent's ComRes poll find that people agree he is ready to be Prime Minister by 46% to 42%. Clearly being seen as shallow and lightweight isn't that much of a hindrance to him.
Cameron's ratings are very positive - but there are negatives lurking under the surface, people do recognise some downsides to the Conservative leader in terms of being a bit insubstantial and shallow. With Brown as the alternative it doesn't matter of course, he is loathed, but when Labour get round to removing him Cameron won't necessarily automatically outshine Brown's replacement.