The UK fleet industry is at odds over whether costs would rise as a consequence of leaving the European Union (EU), according to a poll of Fleet News readers. Almost two-thirds (61 per cent) of respondents believe their bottom line would not be negatively affected, while the remaining 39 per cent feel that fleet costs will increase in the event of the so-called 'Brexit'. The Society of Motor Manufacturers and Traders (SMMT) recently voiced concerns about the potential charges that could be imposed on fleets in the event of a Brexit. An SMMT spokesman said: 'The UK's membership allows components and finished vehicles to be imported and exported across the world's largest single market without tariffs, which helps to keep costs down. 'In the event of a Brexit, we would lose this automatic right and there is no guarantee we would be able to renegotiate such beneficial terms. 'It could take years for new trading deals to be agreed, and we could face tariffs of up to 10 per cent _ a significant cost in an industry with notoriously tight margins.î Further costs could then be passed on to fleet customers through increased rental costs, minimal discounts and higher P11D charges. Recent analysis from The AA indicates that, in the event of Brexit and a possible fall in the price of sterling, fleets could be forced to pay hundreds of pounds more to fill up their vehicles with fuel. The Press Association reports that, in a 'worst case scenarioî, fuel prices could soar by as much as 18.7p per litre. Edmund King, president, The AA, said: 'We don't take a view as to whether the UK should leave the European Union as that is up to people to decide in a referendum. 'However, even before the referendum vote, it seems that financial reports suggest leaving the EU could lead to a sharp fall in the value of the pound which in turn could hit pump prices within days. 'The instability of the pound _ combined with Opec countries already looking to freeze oil output and the usual increase in fuel use during the US motoring season _ could mean a significant rise in costs.î However, the founder of campaign group, FairFuelUK, Howard Cox, labelled The AA's claims 'ill-informedî. 'If the pound remains stable and oil remains low due to over production, then it will still be down to George Osborne what we pay at the pumps.î The RAC was equally cautious about the impact of an EU exit and possible fuel price hikes. Simon Williams, RAC fuel spokesman, said: 'While the RAC has no view on the UK's membership of the EU, the impact on fuel prices of Britain exiting is not likely to be as dramatic as motorists might be led to think. 'While the strength of the pound is a significant factor in the price motorists pay for petrol and diesel due to wholesale fuel being traded in dollars, the oil price is currently a greater influence. 'Opec appears to be sticking with the general principles of its over-production strategy, so there is little reason to expect anything to change drastically in the meantime. 'And, even after that, if the barrel price was to go above $60 it would signal a major move away from Opec's strategy to maintain market share through a lower price and make it financially unattractive for the US to produce oil from fracking.î