There is a huge problem of violence starting in reception classes that seems to be growing. It can take years to get the intervention that's needed. It is so unfair on the other children in these classes and is disrupting learning for everyone.
In my opinion, the whole idea of mainsteam school for all is seriously flawed. These kids often need a completely different approach to their education - one focused on their well-being rather than academic success. The most academically able also need to be able to flourish rather than being held back, as this also causes frustration in potentially high-achievers, particularly ND children, that can lead to further MH issues. Based on personal experience, whilst mixing abilities may sound good in theory, in practice it can be hugely detrimental to all.
We need many many more special schools and a huge investment in early recognition and diagnosis of SEND and MH issues. More importantly, once those with serious problems are diagnosed, they need to be taken out of mainstream classes/schools as early as possible and taken into a more nurturing environment.
Also, IMO, mainstream schools are often too large. The personal and friendly approach where teachers get to know the children over a period of years has often been completely lost. Too often it feels like the children are being processed through the system rather than nurtured to bring out the best in each of them as individuals. I feel that the whole sense of community care has been lost but that is a much bigger issue and huge schools are just one element of that.