5% BTC Spread?

On Blockchain com there is a 5% difference between BTC by and sell prices. How does this work and will the spread be different at another time so that I don't waste 5 bloody percent on what seems to essentially be an added fee? Do any other platforms handle these scenarios any better? I don't see how they can justify such a massive difference to customers.

I am aware that spread has to be exist, like in stock prices where the spread might be a few pennies but the difference between a spot price of £51,900 and £54,150 is very big. Such a big exchange should have the resources to close this gap and not doing this is exploitative.