Why do we have the 11 plus exam?

The 11+ was introduced back in 1944. All 11-12 year-old (Year 6) took the test and those who passed went to grammar school. When comprehensive schools were introduced in 1965, the number of grammar schools began to reduce. There are now only 164 grammar schools. However, the 11+ is still used by grammar schools and some private schools to decide who will be awarded bursaries or have their fees paid in full.