The BBC is reporting today that Lord (Chris) Smith, chair of the Environment Agency, has come out in favour of fracking – the controversial method for extracting gas from shale. In reality his words are not a clearcut endorsement for the practice.

The Beeb points out that Smith said on the Today programme that he only backed fracking if it was accompanied by successful carbon capture & storage, which so far only exists in pilot form.

In fact his concerns are wider. In his speech tonight at the RSA he will say that fracking “potentially ticks the box on energy security, on availability and on cost“.

But he adds: “Does it tick the box on environment? The answer is complex, and is something like ‘up to a point’.” If Britain locks itself into a new generation of gas, “with all the carbon consequences“, it would be unable to reduce the carbon impact of its power generation to zero, he will say.

Lord Smith will also add that fracking needs careful use of drilling technology and rigorous monitoring and inspection. No doubt he is aware of the controversy surrounding the chemicals which are used in the process of extraction – skilfully described in this excellent feature by our environment correspondent, Pilita Clark.

The peer will use his speech to make a broader warning that green issues are sliding down the political agenda despite being among the most important challenges facing the UK.

In a rare intervention by the former Labour culture secretary, the peer will use his first big speech for three years to call for the government to “acknowledge and respect” that environmental policy is essential and not an optional extra.

The comments come as the coalition is shedding several green commitments in order to focus on economic growth. “We can’t abandon either green or growth,” he will say in tonight’s speech.

Lord Smith told me he backed the coalition’s attempts to streamline regulation to make it less bureaucratic. The government has carried out a “red tape challenge” to strip away unnecessary burdens on companies.

But he challenged the focus on cutting legislation, saying there was a reason why many regulations existed. “Because things like putting toxins into our water or