You asked

David Cameron refers to those who accept benefit ‘as a lifestyle choice’. Since he has often referred to such people, I assume he has evidence to back his point. I would therefore like to know what percentage of benefit claimants are living in such a manner and by what criteria they are judged.

We said

The Office for National Statistics only has access to a limited amount of information regarding individuals claiming benefits. This information does not allow an assessment of the benefit dependency of individuals over their lifetime.

More comprehensive benefit information is held by the Department for Work and Pensions (DWP), who publish a wide range of statistics based on this information. Therefore, the DWP would be in a better position to respond to your query.