Very roughly, UK prices are ~£0.2/kwh electrity and ~£2/litre of petrol. Per mile I make that £0.2 for petrol vs £0.045 for electric. Although you could probably get to the 1/10th figure if you always charged on the super-off-peak EV tarrifs.
In previous times they used to offer a tariff called economy 7 which worked in conjunction with so-called storage heaters. They would charge during off-peak times and provide heat during more active hours. (disclaimer, I've never lived in a property on such a scheme but definitely saw a few in my student days)
With today's price it would be 16p/mi for petrol. Their optimal May electricity price gives 1.88p/mi.
https://www.whichev.net/2022/05/13/is-it-cheaper-to-drive-an...
At $5/gal and 20mpg, you'll pay $7.50 for 30 miles.
Can you provide some data for that claim. Are we talking cost per mile travelled eg like for like?