"We're having to compete with hauliers from those other EU countries who are coming into the UK with enough fuel to last all week - they're undercutting our rates, taking our work and destroying British companies."
Escorted by police, the protestors on Wednesday set off from a service station in Kent and will drive in convoys from a highway west of the city, into the centre of London.
In May, several hundred truckers jammed a major route into London in a similar protest.
In addition to the mobile protest, a delegation of hauliers will lobby Parliament on foot in protest at record-high fuel prices.
High fuel prices have sparked several protests across Europe in the last few months.