A greater number of schools across England and Wales have been rated as performing well under a new colour-coded system of grading in the second year of this style of rating being put in place. 

According to governmental data, as many as 333 primary schools across England and Wales managed to achieve the top green rating in 2015. This was an impressive climb from the 236 who achieved this colour grading in 2014, showing that there was a marked effort towards improvement over the course of the year. 

There was also an encouraging fall in the number of schools that were achieving the lowest red rating. In 2015, these dropped from a total of 81 to just 58 as more schools improved markedly on the year that came before. 

In the new system, primary schools are given a clear and concise rating of green, yellow, amber or red, with each colour in the scheme showing how much help and assistance a school would need to become a high performer. 

Green schools are those where there is a track record of achieving and sustaining high levels of learner outcomes, can demonstrate resilience at all levels and are challenged to move forward and sustain their excellence. 

Yellow schools are those where there are good levels of learner outcomes in key performance indicators, an understanding of where they need to improve to reach their targets and a range of aspects that are in self improvement. 

Amber schools differ from yellow in that the school does not know where they need to improve to get better results, their performance aspects are not improving quickly enough and needs special intervention to stop it falling to an even lower level. 

Finally, those schools that are adjudged to be in the red rating band are experiencing declining performance levels, and need intensive support to bring things back under control and ensure improvements. They will receive intervention from government bodies to help make them a success. 

Education Minister Huw Lewis said: "This is not about crude league tables or labelling schools - it is about directing the right support to schools that need it and ensuring improvements right across our school system. 

"Ultimately it is about raising standards and supporting our schools to self improve. 

"Categorisation is also a system that delivers for all learners. Schools cannot just rely on the performance of their top students as any school performing below the agreed minimum standard for its free school meal pupils will not be put into the green category."

However, some leaders in North Wales have complained that there is a problem with the system in that the performance of a single student can bring the school's overall rating down very quickly. 

Liberal Democrat AM Aled Roberts said: "The new system is certainly an improvement on banding [the previous process] but it still does not take into account variations within a specific school. 

"A green grade overall can mask any number of shortcomings in individual departments in the same way as a red grade can mask examples of excellence in a school."