The Education and Skills Act 2008 increased the minimum age at which young people in England can leave learning. This requires them to continue in education or training to the age of 17 from 2013 and to 18 from 2015. Young people will be able to choose whether to stay in full-time education, undertake work-based learning such as an Apprenticeship, or part-time education or training if they are employed, self-employed or volunteering for more than 20 hours per week.
So for children intending to do A level's there is no change. Children wanting to leave school and get a job can still do so as long as the job has a "training element" to it, eg. you can leave school at 16 to become an apprentice hairdresser (attending college part-time) but not to sweep the floor of the hairdressers.