Music is compulsory for all children in key stages 1-3 in maintained schools. One of the requirements of the National Curriculum is that pupils are taught to play musical instruments. Schools are not permitted to charge for teaching that is required by the National Curriculum.
The Government is investing £75m in 2015-16 in a network of music education hubs. Music education hubs have four core roles, one of which is to ensure that every child aged 5-18 learns to play a musical instrument through whole class ensemble teaching. Data published by Arts Council England in March 2015 showed that 596,820 pupils in the academic year 2013/14 learned to play an instrument through whole class ensemble teaching. This teaching is provided free for pupils.
The data is available here: http://www.artscouncil.org.uk/media/uploads/Music_Education_Hubs_2014_Report_final_March_2015.pdf.
Arts Council England will publish data for the 2014-15 academic year in due course. This will include more extensive data on the number of pupils who have singing or instrumental lessons.