Which is more cheaper to running on petrol or diesel?

[TheFlyingPostman]

(Apologize for my bad English is not my first language) I am try to looking for two used cars to buy is Honda Jazz 1.3 DSI 2006 CVT 66,000miles for £2,700 do 48mpg and Toyota Yaris 1.4D4D MMT 2005 63,000 miles for £3,200 do 64mpg, I have took both out for a test driver and I am not sure which it will be cheap to running for in the next 5 years?. I do travel 22,000 miles a year to London, the Jazz is very very cheap to insure than Yaris but the Jazz road tax is cost more than Yaris.
My mate thinks the petrol it will be cheap because of less engine maintenance for a example diesel oil change every 6,000 miles but petrol change every 10,000 miles, the risk of replace diesel's turbo, injection, high fuel pressure pump and etc. when it go wrong which would it make more expensive replace in garage than the petrol in total 5 years? Jazz which does not have any turbo, high pressure fuel pump do you reckon the petrol will it be cheaper???

My mathematics is sucks!

Fab.

[ZX10R NIN]

The first thing to ask yourself is how many miles you do a year? If it's less than 10k a year then petrol is your best option after that I'd weigh up the pros & cons.