I mean the maths is simple enough if you round up.

ICE @ 40 MPG: ~22.6p per mile for diesel EV: ~3p per mile for off-peak home charging.

The difference from 23 to 3 is a decrease of 20, which is an 86.96% decrease.

https://www.theguardian.com/money/2026/sep/28/price-of-diese...