The Greens have condemned the “scandalous” lack of focus on tackling Britain’s environmental crisis in the election campaign, attacking both main parties.

Party co-leader Caroline Lucas criticised both the Conservatives and Labour for “almost environment-free” manifestos – even as climate change is “accelerating”.

She took her protest to both Downing Street and Labour's London headquarters, posing with a giant green question mark asking: “Where is the environment?”

Speaking to supporters outside Parliament, Ms Lucas said: “Without a prosperous and thriving environment, there cannot be a prosperous and thriving economy.

“There is no point talking about strong and stable leadership if you don’t have a strong and stable environment.

“Where is the environment in this election campaign? It is nothing short of scandalous that the other parties are not talking about it.”

Ms Lucas sent letters to Theresa May and to Jeremy Corbyn to express how “appalled” she is at the lack of discussion about the environment during the seven-week campaign.

Her letter to the Labour leader noted a “number of welcome environment announcements”, but said his party was failing on fossil fuels and airport expansion.

In the Conservative manifesto, Ms Lucas attacked “one paltry mention” of the air pollution crisis, while fracking would be “forced” on communities.

Meanwhile, the Prime Minister was refusing to give legal commitments to the environment in the Brexit negotiations, posing a “fundamental threat” to EU-derived protections.

Ms Lucas pointed to the fact that 2016 was the “hottest year on record” as evidence that the threat from climate change is growing.

Britain was also “one of the most nature-depleted countries”, with 66 per cent of wildlife and nature in decline and 15 per cent at risk of extinction.

The Greens have published a separate environment manifesto, including plans to:

* Pass an Environmental Protection Act - to protect the natural world after Brexit, through a new regulator and court.

* End the monopoly of the Big Six energy companies by “building democratic, locally owned alternatives”.

* End plastic waste by introducing a bottle deposit scheme, to stop 16m plastic bottles ending up in environment every day.

As well as defending Ms Lucas’ Brighton seat, the Greens are targeting Labour seats in Bristol and Norwich and Conservative seats in the Isle of Wight and Portsmouth.