The IB DP is offered by most of the 83 private IB schools in the UK.
Subjects are offered at Higher Level, Standard Level or both. To qualify for the Diploma a student must pass at least 3 subjects at Higher Level and a total of 6 from the following list:
A candidate can receive between 1 and 7 points in each category. He or she can also get up to 3 points for The Theory of Knowledge and The Extended Essay – thereby meaning a maximum score of 45 points which a small number of candidates actually achieve. A diploma is given to those scoring 24 or more.
The Theory of Knowledge is obligatory and similar to the subject of Philosophy covering:
Students must write an extended essay up to 4000 words on an independent topic within the subjects being taught within the IB. This is intended to show the kind of independence, analysis and writing skills expected by universities. It is a valuable first experience of individual research.
You can see from the above that the DP requires a broader range of knowledge and skills than those demanded by 3 similar A level subjects. The huge difference is that a linguist is challenged to learn a science and that a scientist must learn a foreign language. This keeps university options open longer, especially when no one can predict what professional life will demand in many years from now.
It has been suggested that those students aiming for a medical or science degree should also take a specific science A level, although universities have confirmed that this is not a general requirement. Plainly it is best to check with the preferred universities before embarking upon study.