wrong fuel in hdi

[rd070707]

Alright guys my dad has put 30 quid of unleaded in his 307 hdi seimens today and drove 2 miles. Now he doesn't want to start her again but said she wouldnt go anyway, as it says economy mode on the dash. Now I know when I had mine, the economy mode refered to the battery being low but is there any chance it's to do with the fuel he's put in?

Otherwise I may get planet on it