DS has started at one of the Surrey grammars and has just had his mid term report. He’s done well in all areas except maths. Like a lot of grammar school boys I guess he was always top of his class in maths and now that is in no way the case. I don’t want him to get into a negative spiral of poor confidence with maths.
Does anyone have any advice on how his confidence can be rebuilt and he eventually achieves a good GCSE grade? Thank you.

He needs to talk to his teacher and ask for additional help and maybe do more questions. A lot of 'ability' in maths is actually confidence to tackle unfamiliar problems.

Is it specific topics or just a general 'feeling'?

Doodlemaths app has a secondary age version. My two use the primary version. My DD's confidence has rocketed. 10 minutes a day and the algorithm works out how to pitch the questions against National Curriculum and the child's areas of strength/weakness. I might have a discount code lingering about for new subscriptions if you want to PM me

There is no need to pay for anything - there are loads of free resources I can point to.

There is an option with the app I mentioned to use for free, but it only allows limited use. We ended up subscribing as the kids themselves wanted to do more and think of it as a treat

My experience of helping them with areas of difficulty is that it is very easy to make things worse and reduce confidence. Whatever you choose make sure it is fun and reward effort rather than results

Experience is that maths teachers in GS can go very fast while some pupils need more time to understand and practice.
( In a few cases GS teachers get away with not being terribly good at explaining because many pupils pick things up quickly and help out their mates)

Agree, first step should be to talk it through with his teacher. Its their job not to 'leave anyone behind'.

In some cases the teacher wont allow time in class / set homework to work through all examples in a text book. If DC isn't confident then it may be worth working through more methodically. Something to discuss with teacher.

Almost agree

Just to add; children are very good at assessing where they rank according to their peers and every class has a range of ability. There will always be a top and a bottom. Most higher ability pupils put in more effort. There are exceptions of course. This could be one.

His class teacher is the person to talk to in the first instance and then the rest will be down to him.

More difficult issues arise with pupils 'hot housed' through the 11+ but I don't get that impression from the first post.

I actually disagree with this - it is more obvious in primary where there tends to still be the "top table" differentiation, but, with a few exceptions, less obvious in secondary as the work becomes harder and there are more subjects. A child may be very good at English and History, but less able at Maths and Chemistry, for example. Most children in Secondary are "ok" at most subjects, not so great in one or two and pretty good in one or two, rather than being stellar in all of them, therefore their peers cannot easily "rank" them, nor understand the nuances of ability, in thw way you describe. In the same way I don't think students are able to identify how well they have done in an exam or test - they might come out thinking it was awful, but not realise that if everyone else found it very hard, they could still get a good grade (for example in GCSE/A levels), or vice versa.

OP your son may feel he is not good at maths (or it may be you that feels he is not good at maths - I am not entirely sure!), but get him to go and see his class teacher as he may be doing better than he thinks or there may be a simple fix that the teacher can hep with but they will be the best person to advise and help him!

Thanks so much everyone for such a useful range of replies and suggestions. I think DS was pulled up short when he performed badly in a test and that has been reflected in his mid term report. He was not hot housed, he had 1 hour a week of maths tuition from a friend of mine who is a primary school teacher but not a professional tutor. He was always on the top table but now there are kids who are more able than him and it seems to have hit his confidence. Whereas in other subjects the gap is not so apparent.
I will certainly look at doodlemaths. He definitely could be putting in a bit more effort, he has a tendency to rest on his laurels. I’m hoping the meet up with his maths teacher will also be helpful. I’m not going to get heavy handed though as the last thing I want is for him to get a “ maths complex” ( which I had when I was at school).

Guest55, if you could suggest some free resources too that would be really helpful.