The price cap is defined by a strict calculation methodology - it can’t be changed on a whim. The April price cap is going up, because it is based on prices over the winter period, further, it’s not spot prices, it’s forward prices (ie the price paid by energy suppliers to buy it). Forward prices have only recently declined. So the price is going up 20%, plus customers are losing the £400 support.
The better news is that by next winter, lower wholesale prices will be included in the cap, last time I looked it seemed to be around £2,100ish, equivalent to now (now has the EPG of £2,500 less £400 of support). So the price is currently artificially ‘lower’ at £2,100 (not low at all I realise), whereas this winter it will be at that level without support.
New suppliers now have to pay a ‘market stabilisation charge’ to the old supplier to reflect the cost of hedging, so it will be difficult to undercut the price cap by much.
Current lower prices over winter have been as a result of warmer weather (hard to believe at points) plus lower Chinese demand due to surging Covid cases. Chinese demand is likely to increase, and obviously Ukraine volatility remains present - not much has been solved tbh.