50%? If I compare the same spec I currently use (13", 8 GB, 512GB SSD) it's a couple of hundred on the education price (which is the relevant one for me, and hence the one I watch, but I assume scales with the non-education price).
If you mean comparing UK with US prices, remember that US prices don't include taxes, UK prices do, and all companies use their own exchange rates (hedging against fluctuations) rather than today's market rate. The UK price is always higher than the US one * today's rate, my comparison with simply with the recent UK prices - these had not, that I'd seen, changed with exchange rate, but you'd expect that the release of a new model would be the point at which they'd include that.