By Jessica Frank-Keyes The graduate visa system “does not offer any value to the skills of the UK labour market”, a Conservative MP has claimed. A government-commissioned review into the UK’s graduate visa route reported yesterday that it had not found widespread abuse of the route and said it should remain in place. The visa allows overseas students to stay in the UK for two or three years after graduation. But Professor Brian Bell, chairman of the independent Migration Advisory Committee (Mac), which conducted the review, appearing at the Home Affairs select committee this morning, was quizz…