the invention provides a hydrocarbon composition for use in ci engines , said composition comprising a blend of hydrocarbons derived from a ltft and from a htft process , said ltft derived hydrocarbon being blended with said htft derived hydrocarbon in a volumetric ratio of from 1 : 20 to 20 : 1 . the invention further provides a process for the production of the hydrocarbon composition and a the fuel composition including , in addition to the hydrocarbon composition , one or more component selected from the group including a crude oil derived diesel fuel , a crude oil derived naphtha , a lubricant or light cycle oil .