Avid bloggers and observers of London politics might have noticed that James Cleverly, the Conservative Assembly Member for Bexley and Bromley and Boris Johnson’s Ambassador for Youth, is intent on defending a muddled decision by Boris Johnson over vehicle emissions and in the process sought to criticise me and the Liberal Democrats.

Of course James is entitled to his own views but he’s wrong when he says there’s no evidence the Low Emission Zone is working. No lesser source than the Mayor has said (press release 2nd February): “…the Low Emission Zone has been successful in tackling the worst polluters, and will continue to play an important role…..”

If evidence is needed that LEZ has had a positive impact just take a look at this report on the impact of the LEZ. On page nine of the Transport for London’s report examining the impact of the LEZ it states:

TfL’s camera-based monitoring of the emissions profile of vehicles in London has provided robust evidence of the success of the first phases of the scheme. As is shown in the figure below, April 2008 saw a 98 per cent compliance rate with the requirements of the first phase of the scheme-based on vehicle kilometres operated. In terms of unique vehicles seen within the zone (ie at least once), the compliance rate was 96 per cent.

And if that doesn’t impress you take a look at this further quote from the same report:

This means that about one-third of the heavier goods vehicles operating in Greater London are significantly cleaner than they were one year ago, and that London is already benefiting from reduced emissions.

So we Lib Dems are clear that the third phase of the LEZ, extending to small vans, should go ahead on plan. Many are old, diesel powered, inefficient and so damaging to health.

Yet in one respect James Cleverly does have a point. The needs of small businesses and voluntary organizations are important. No one wishes to see a small business or voluntary organization face unreasonable burdens in adapting or replacing vans or minibuses. However, instead of scrapping new targets from being implemented from October of next year, small businesses and voluntary organisations must be helped to adapt their polluting vehicles vans and minibuses, or to purchase new vehicles.

It is simply daft to create a situation where it is claimed that it is absolutely necessary to trade off improvements in air quality with the needs of businesses. In fact the two things are in many respects the very opposite of a trade off. For example poor air quality often leads to absenteeism at work, which hits businesses. Most significantly there is an immense health bill from air pollution, especially from small particles (PM10) – a large bill that ultimately has to be picked up by taxpayers and lets not forget businesses are taxpayers. And of course if small businesses are given help to purchase low emission vehicles that might also help save some jobs in the motor industry, something that is desperately needed at present.

Boris Johnson says he is pro-environment, then takes a retrograde step, instead of having the courage of his (stated anyway) convictions. And here I think it is worth quoting the national leader of the Conservative Party.

Only last year David Cameron stated in the Daily Telegraph: “The truth is it’s not we can’t afford to go green – it’s that we can’t afford not to go green.”

When you look at the facts over London air quality, when you consider that it leads to over 1,000 Londoners dying prematurely each year and when you look at the true costs of London’s air quality for individuals and businesses, I couldn’t agree more.

Mike Tuffrey is Leader of the Liberal Democrat London Assembly Group.