Teenagers will be forced to continue studying English and maths if they fail to get good enough marks in the two subjects at GCSEs under government changes.

Under the rules that come into force this week, 16-year-olds will be required to get at least a C grade in the two subjects or face carrying on until they do. Ministers are keen to improve the performance of British schoolchildren in what were called the "most important [subjects] in the world".

The education secretary, Michael Gove, said: "Good qualifications in English and maths are what employers demand before all others. They are, quite simply, the most important vocational skills a young person can have. Young people must be able to demonstrate their understanding of these subjects."

About one in five young people in England continue studying maths past the age of 16, compared with the majority of school children in other developed nations.

The proposal was first put forward by Alison Wolf, the Sir Roy Griffiths professor of public sector management at King's College London, in her 2011 review of vocational education.

She said it was scandalous that half of 16-year-olds were leaving school without good GCSEs in English and maths and warned that it was a real failure of the education system that many of these youngsters would still not have these qualifications at age 18.

Wolf said the move would have a "hugely positive impact on the ability of hundreds of thousands of young people to get good jobs." She said she was delighted to see the proposal being implemented and the reform comes as the education participation age is raised to 17. In 2015, it will be raised to 18.

Figures show among young people aged 19 last year, 285,000 left school at age 16 without a C or higher in both English and maths; by the time they were 19, 255,000 had still not reached this level, the Department for Education (DfE) said. More than 20% of those who had not gained a good grade at age 16 in English continued studying it, along with 23% of those who had not got a C or better in maths.

The DfE said teenagers without C grades or higher in English and maths would ideally continue studying for GCSEs in these subjects, although they could also take other qualifications such as functional skills and maths courses accredited by the exams regulator Ofqual as a stepping stone to GCSEs. The English and maths results of 16- to 19-year-olds who did not gain these key GCSEs will also be reported in annual school league tables, the department said.

A poll published by the Sutton Trust last month found that nearly two-thirds of 11- to 16-year-olds in England and Wales were in favour of young people at school or college studying maths and English up to the age of 18.