Any commercial company worth its salt is going to have people whose entire job is working out how to exploit an opportunity like this, to pitch their products in front of school-children. They have 365 days to work on it and only 1 hour to fill. Teachers meanwhile, have to full every other hour of the school year with lessons planned to the best of their ability. They have neither the time nor the expertise to counter the pitch, and no incentive if a diktat comes down from on high that they must do this. It is a scandal that companies (and not even UK ones) are given such unfettered access to our kids on an annual basis.
Coding shouldn't even be a priority, not even for one hour. You can't *do* anything in that time and there can't be a child in the country who isn't already aware of the importance of computers and the fact that someone needs to program them. If they are interested, they've probably googled their way to the most common options for learning. If not, they won't become interested by watching a teacher discover that every other primary school in the land is also trying to access www.corporate-advert.com at this precise moment in time, or that "no, the school's internal network can't cope with every single computer in the building logging into the domain at the same time".
Meanwhile, the curriculum continues to narrow to strangulation point. In the UK, the only things that are tested (and therefore the only things that schools are rewarded for) at Key Stage 2 are English and Maths. All that time on science or humanities that actually makes the curriculum interesting gets you no points at the end of Year 6. Any politician who actually understood the free market could predict the outcome of that selective environment, but ... sigh.