Prime Minister David Cameron insists the Conservatives have been the greenest government ever.
The Tories have taken criticism this week after unveiling plans to slash subsidies to solar power projects, with opponents claiming it would take Britain's renewable energy sector "back to the dark ages".
And questions have been raised about the UK's decision to suspend a ban on a type of pesticide linked to serious harm in bees and pollinators.
However, Mr Cameron hit back at his detractors and argued his administration had done a great deal for the environment and renewable energy.
Speaking at the Royal Welsh Show in Builth Wells, mid Wales, he said: "I believe we've been the greenest government ever and we've made great pledges in the last parliament which we've kept - like the world's first green investment bank, which is spending billions of pounds investing in green energy.
"We have seen a massive increase in investments in renewable energies ... we are now close to having 10% of our electricity needs being met by onshore wind. We have the world's largest offshore wind market."
Mr Cameron spoke to reporters just as news came in that there were to be changes to the rules on two neonicotinoid pesticides. Farmers' groups have welcomed the move, but environmentalists have condemned it.
The PM said: "We should follow the science. The EU put in place the ban on neonics, but we have to be informed by the science and if scientists start telling us that these things are safer than they thought then perhaps we can license them.
"But we do have to think very carefully about these things. My view as someone from a rural constituency is that we should listen to the local experts such as the beekeepers and see what they have to say."
The National Farmers' Union was pleased about the relaxing of rules on two types of neonicotinoid pesticides, but claimed the changes did not go far enough.
NFU vice president Guy Smith said: "We're glad to finally see a positive result.
"However, we know that this isn't enough and the extremely limited nature of this authorisation is unfortunately not going to help the vast majority of farmers in need of the protection."
However, Wales's natural resources minister and Labour Assembly Member Carl Sargeant questioned claims the Tories were the party of the environment.
He said: "The Tories are on a crusade to end renewable energy at whatever cost: they don't care about the environment, they don't care about people's jobs."
And responding to Mr Cameron's insistence that the Conservatives have been the greenest government ever, Friends of the Earth's chief executive Craig Bennett said: "David Cameron's administration is rapidly becoming one of the greyest governments we've ever had.
"Barely a week has gone by without the new government announcing a plan to boost climate-wrecking fossil fuels or to undermine renewable power or energy saving measures. They have also given farmers the go-ahead to use 'banned' pesticides, despite huge scientific evidence of the harm caused to bees.
"This Government is clearly putting outdated ideology and the short-term interests of its energy company and agri-business friends first, instead of building the clean future that's so urgently required."
A spokesman for the Department of Rural Affairs and Food said: "We have fully applied the precautionary ban on the use of neonicotinoids introduced by the EU, and we make decisions on pesticides based on the science only once the regulators are satisfied they are safe to people and the environment.
"Based on the evidence, we have followed the advice of the UK Expert Committee on Pesticides and our Chief Scientist that a limited emergency authorisation of two pesticides requested by farmers should be granted in areas where oil rape crops are at greatest risk of pest damage."