Shell and BP unmoved by price fixing probe MPs and officials have suggested the oil price could be vulnerable to being rigged in the same way as the Libor lending rate was rigged by banks, in a scandal that led to senior resignations and huge regulatory fines. Tory MP Robert Halfon, who has led a campaign calling for a full investigation into alleged cartels and market manipulation in the oil market for the past three years, told BBC Radio 4's Today programme: "Clearly there has been a problem, there needs to be a full inquiry." Both oil majors have petrol forecourts across the UK and, as well as the reaction of the markets, will be keen to manage the risk of reputational damage among motorists. "Public relations is important to oil companies so they will be taking it seriously," one industry source said.