One of Gordon Brown's first acts on coming into office – after having to write that disturbing memo about what to do in the event of nuclear attack – was to halt government use of the term "War on Terror". Well, while he's banning counterproductive soundbites how's about getting rid of "leading the fight against climate change" as well.

It may be leading the world in climate change PR and spin, but can the UK seriously continue to cling to the pretence that it is in some way established as the world's premier sustainable economy.

The government's climate change strategy has received a series of body blows in recent weeks with its flagship climate change bill facing repeated attack from influential parliamentary committees for being far too lenient; the inconsistency of its emission reduction targets and support for airport expansion highlighted by a bunch of hippies (sorry protestors) at Heathrow; and its reaction to summer floods leaving plenty to be desired.

Now the most damaging revelation yet has emerged today with reports in The Guardian that civil servants have been briefing ministers that they will not hit EU targets to generate 20 percent of energy from renewable sources and should investigate ways to water down or wriggle out of the targets.

According to a briefing document obtained by the paper, the UK "has achieved little so far on renewables" and has little hope of hitting the EU targets. It also urges ministers to examine "what options there are for statistical interpretations of the target that would make it easier to achieve", and advises that they should try and get nuclear power and investments in renewable energy in the developing world included in the targets.

Needless to say the government sought to distance itself from the leaked memo with a spokesman for the Department for Business, Enterprise and Regulatory Reform claiming the government "is committed to renewables and reducing emissions in line with EU targets".

Well, that may be the case but some of its most influential civil servants blatantly are not.

What this latest revelation confirms is that it is time for the government to can the rhetoric about it being a leader on climate change and accept that the UK's global warming policy is so far from exemplary that each time Environment Secretary Hilary Benn talks about "our leading position internationally" he is more likely to be greeted by laughter than admiration.

Ever since it unveiled the Stern Report last year the government has been keen to paint itself as being at the vanguard of international attempts to tackle climate change, but claims such as those made recently by Benn that the "UK should be proud of its record on tackling climate change" increasingly fail to stack up against the available evidence.

What's more this pioneering rhetoric is dangerous on the grounds that it can only lead to complacency. How urgent will individuals and businesses perceive the need to modify behaviours and limit carbon emissions when our government keeps on telling us we are already amongst the world's greenest economies? No one is suggesting the government spokespeople should take on the tone of apocalyptic doom mongers, but any serious reduction in the carbon intensity of our economy will only be possible if we fully accept how far the UK has to go in adopting low carbon practices.

The fact is that we are making good progress in some areas and regressing in others. To assess this mixed bag and insist we are taking a leadership position would be like the US claiming it has the best health service on the grounds it has some of the best medical universities, or Cuba insisting it has the world's best education system on the evidence of some high literacy rates.   

Of course, it is not all bad. The government's support for emissions trading and willingness to tighten up the EU scheme has been admirable, while London has emerged as the world's carbon trading capital - which has to be A Good Thing despite current reservations at the effectiveness of such markets. Many UK firms are also taking up genuine leadership positions and investing heavily in greener business models and clean technologies.

However, these isolated trends aside the government's overall environmental record remains less than impressive. Even the areas it points to as evidence of the UK's supposed leadership position are deeply flawed.

For example, Benn's insistence on defending the UK's record by claiming "we are on track to meet and go beyond our Kyoto target" may be accurate but is also highly disingenuous as it has primarily been achieved as a result of the "dash to gas" rather than the success of any government policy.

Equally, the Climate Change Bill may be the first of its kind anywhere in the world, but, as repeated independent experts have now pointed out, it is pretty close to worthless in its current form. Without proper teeth and the inclusion of every sector of the economy the legislation looks more like window dressing than a serious attempt to underpin a low carbon economy.

Meanwhile, if you look at the two most important sectors of the economy for tackling climate change, energy and transport, the government's policy is in disarray.

Renewable energy accounts for around two percent of the UK's energy mix, compared to seven percent across the EU and 13 percent in Germany, while the government's Renewables Obligation and Low Carbon Buildings Programme have both been criticised as being underfunded and ineffective. New windfarms, meanwhile, continue to be repeatedly blocked by local planning legislation.

The transport policy is possibly worse still, with the cost of public transport having risen massively in real terms as the cost of motoring has fallen and the government apparently focused more on road and airport expansion than on enhancing the public transport network.

Faced with this record embarrassment alone should be enough to get ministers to shut up about the UK leading the fight against climate change, but sadly embarrassment is an emotion that appears to have been removed from anyone seeking a career in parliament. The government may try to defend its record as a low carbon pioneer by pointing to the awful environmental record of governments such as the US and China, but that's like feeling proud because you are the fastest tortoise.

The current perpetuation of the Blair government's climate change mythology is so damaging because it makes real action on climate change less rather than more likely.

Why should the government ditch its renewable energy strategy in favour of the far more effective German model if its ministers believe, in contradiction of all available evidence, that their strategy is better? Why should it increase investment in greener transport if the UK is going to hit its Kyoto obligations anyway? Why should it encourage micro generation of energy when it would be cheaper to lobby for a watering down of EU targets? Why should it deliver more incentives for green businesses if we are already putting our international rivals to shame?

If business leaders want the incentives and legal framework they believe is necessary to accelerate the transition to a low carbon economy then they should be challenging the government's claim that it has the world's pre-eminent environmental policy at every turn. The myth that the UK is a low carbon pioneer needs puncturing and scrapping the government's hubristic insistence that its strategy is without rival would be the quickest and most effective way of doing so.