While actively supporting the improvements to air quality in London, the group has a number of fundamental concerns about the proposals put forward by Transport for London (TfL) in their consultation:

"The cost/benefit ratio of the scheme remains unclear.

"The estimated costs until 2015 are over half a billion pounds, £130 million of tax payers' money to set up and operate, and £390m from businesses to comply.

"Yet, the scheme only accelerates what would happen with natural vehicle replacement by four years, raising doubts over the cost effectiveness for London of the scheme in its current form.

"It is unclear what further restrictions will be introduced by TfL in 2010, with particular queries over whether light goods vehicles, nitrogen oxides and additional particulate matter requirements will be included.

"There is also concern over the lack of detail on the method used to classify car derived vans, which could potentially have significant impacts on many of London's small businesses.

"It is imperative that the London Low Emission Zone successfully delivers meaningful improvements first time round.

"This scheme is viewed as a blue print for others to follow in Britain and the rest of Europe yet relies heavily on assumptions about compliance, effectiveness of the proposed enforcement regime and even the implementation of engineering technology that does not yet exist.

The joint stakeholder group includes the British Vehicle Rental and Leasing Association, CBI, Confederation of Passenger Transport, Federation of Small Businesses, Freight Transport Association, London First and Road Haulage Association.