A bursary is a payment received by training teachers. This is available for many subjects, some subjects receive £26,000 for an academic year. However, RE only receives £9,000. This doesn't do justice to the subject because of how complex and difficult the subject is to teach.
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RE is a subject which doesn't have a set curriculum, each school across the country is teaching something different. This requires RE teachers to have an enhanced subject knowledge. It's a subject of sensitivity which requires careful thought to phrasing and explaining of content unlike some subjects which just state the fact. Religion is complex and teaching it is not an easy task and it's such an important subject as religion shapes our society. Check out Gov page for funding in ITT 2019-2020.