When we put questions to the parties ahead of the European elections last year, the Green party performed miserably, attracting considerable criticism for a range of policies from banning GM research to pushing alternative medicine for the treatment of cancer.

Since then, and in direct response to our criticism, more rational elements in the party have made an effort to reform policy in a number of areas to ensure that it has a scientific basis. Have their efforts paid off?

The Green party manifesto is considerably more polished than last year's, with a focus on radical left policies centred on community, "fairness" and of course the environment. Radical action on climate change is promised, with the party pushing for reductions in CO 2 emissions of 10% a year, achieved mostly through punitive measures against businesses such as heavy taxation on water consumption and air travel.

In fact, reading their policies on climate is like being faced with a sort of "anti-Ukip", and in many ways – while well-intentioned – equally unrealistic.

On a more positive note, the Greens are excellent on drugs policy, and it is refreshing to see a party highlighting the issue of managing Britain's water supplies, a problem that is likely to loom much larger in the future.

So how do they score on our questions?

Brian Cox: Science funding

Do you plan to maintain Britain's science budget below the European average?

The Greens admit, refreshingly, that they don't yet know what they would spend on scientific research, and focus instead on a "radical commitment" to jobs in high-tech manufacturing and research as part of their wider, ambitious plans to reshape the economy into a nicer, greener form. This isn't an analysis of economic policy, which I suspect is a good thing for the Greens, but certainly they appear to understand the importance of science and technology to Britain's future prosperity.

Alternative medicine

If the balance of evidence suggests that a treatment does not perform any better than placebo, should it be supported by the NHS?

In a welcome U-turn since last year, Redding states that, "Our policy is that any medicine or treatment available on the NHS should be backed up by scientific evidence." Their manifesto uses rather more compromising language, likely reflecting the internal debates in the party over this policy over the past year, pledging to, "make available on the NHS complementary medicines that are cost-effective and have been shown to work." Which is pretty much none of them.

Interestingly, they also seek to reform the labelling of medicines, with a pledge to make sure they carry an accurate list of all ingredients. Presumably homeopathic remedies would carry a blank label.

Simon Singh: Libel reform

What will your party do to reduce the chilling effect of our libel laws on science? Currently there is no statutory public interest defence, so scientists risk running the gauntlet of London's High Court if they publish material they believe to be in the public interest, but that a major corporation or litigious charlatan believes to be libellous.



Party leader Caroline Lucas is herself a signatory to the Libel Reform Campaign pledge, so no problems here.

Climate change/Energy

Should nuclear power be part of our country's strategy for reducing greenhouse gas emissions? How soon can we bring new plants online?



The Greens energy policy is noble, and I would love to believe that it could happen, but the idea of making a 65% cut in CO 2 emissions by 2020 through energy efficiency and renewable energy projects alone seems far-fetched. Unlike the Liberal Democrats, the Greens' dislike for nuclear energy is ideological, but both parties would benefit from presenting a clearer, realistic analysis of how such ambitious targets would be achieved.

David Nutt: Drugs policy



To what extent should drug policy be based on scientific evidence? What evidence, if any, would you require to declassify a drug?

Drug policy is the highlight of the Green manifesto, and by far their strongest policy area. Their approach is based on the recognition that drug harm is ultimately a public health problem, not a criminal issue. The Greens also understand that prohibition itself can cause harm, which logically leads to an evidence-based policy of weighing up "any possible health risks from a particular substance against the social harm of criminalising, for example, millions of cannabis users".

Campaigners have noted that the Greens, and the Lib Dems, have slightly watered down some of their views on drug policy for their manifestos.

They should trust the public and be bold.

Animal testing

Is animal testing necessary? Are the ethical concerns outweighed by the benefits? How would you like to see regulations on animal testing change under your government, if at all?

The same can't be said for their policies on animal testing, which remain an unmitigated disaster.

While we're all entitled to our ethical opinions, the party continues to make statements that are about as grounded in reality as Narnia, from the baseless assertion that animal testing somehow increases the risk of adverse reactions in medicine, to the persistent myth that researchers are not interested in better, cheaper alternatives.

There's also a worrying failure to understand that animal research is not simply used for drug testing, but is the foundation of basic biomedical research. Immunology would barely exist as a research discipline without a ready supply of lab mice. As blogger Gimpy puts it: "They have no understanding of scientific research or medicine."

Incidentally, the "independent patient safety organisation" referred to in the Greens' answer – the Safer Medicines Trust – lists Green party leader Caroline Lucas MEP among its patrons. Independent?

Petra Boynton: Public health

How will your party ensure public health/education campaigns are underpinned by evidence, and how will you evaluate their success? PR companies are increasingly influential in directing both the content and delivery of public campaigns, frequently at the expense of expertise from scientists, healthcare providers and academics.

"Campaigns should be piloted and evaluated, using comparative before-and-after surveys or other means of measuring public awareness, and rolled out to wider populations only if shown to be effective."

With this statement, the Greens join a rapidly emerging cross-party consensus on evidence-based public health campaigns.

Genetic engineering/Stem cell research

Should Britain be at the forefront of research in these areas? What benefits do you believe such research will bring for society?



Happy with stem cell research, the Greens maintain an ideological objection to GM crops. To be fair, they have made some progress since last year in distinguishing between GM crops and wider GM research, which they are happy to let continue. But as with animal testing, the party seems to be in thrall to scientifically illiterate activists.

There are of course some genuine concerns over the behaviour of companies like Monsanto, and there will always be a need to scrutinise claims made for new technologies, but increasingly elements of the Green movement – notably Greenpeace – have adopted a hysterical and unscientific tone on GM food that misinforms the public and prevents sensible debate. The party would do well to step back and engage with independent scientists to improve its understanding of current research.

Ben Goldacre: Pharmaceutical regulation

Do you believe pharmaceutical companies should be forced to publish all the research data they have on the potential benefits and harms of drugs they manufacture?

The Greens go further, and state that all scientific research institutions should publish all relevant research data – a nice idea in theory, although see the caveats I mentioned in my response to Ukip earlier in the week.

The declaration that in order to open up drug production in poorer nations "[drug design] information should be regarded as public property not commercial data" needs considerable clarification. Drug development may cost hundreds of millions of dollars, and Greens should aim to work with pharmaceutical companies to come up with something fair to all parties, rather than simply demanding that they hand over expensive commercial data to competitors.

Conclusion

Their policy in some areas is excellent, and it's tempting to be generous to the Greens. As a party they're well intentioned and admit that they are in the midst of a process of reform:

"We have recently completed a radical overhaul of our health policies which was extremely encouraging. This saw us adopt far stronger policies in areas like complementary therapies and stem cell research and we're intending to approach the science and technology chapters of our policies in the same constructive fashion."

Unfortunately that reform hasn't come quickly enough for this election, and it remains to be seen how entrenched the bad science in areas such as animal testing and GM really is. A lot of work still needs to be done to make the Green party electable on science issues, and it needs to engage with the scientific community to get a much more realistic and balanced understanding of modern science.

Progress has been made, and party members like Redding deserve respect for their achievements so far, but they have a long way to go.