New drone footage has revealed the spread of US-style mega-farms in Britain and worldwide – after MEPs voted to slash funding for them.

The aerial film was taken to show the scale of industrial sheds that mostly house farm animals permanently indoors.

Intensive farming is blamed for helping to accelerate climate change, driving species loss, emitting damaging slurry and nitrates, putting smaller farmers out of business and causing large-scale animal suffering by cramming creatures into windowless buildings with no outdoors access.

The UK has an estimated 800 mega-farms, after an increase of at least 26 per cent since 2011.

The biggest mega-farms house more than a million chickens, 20,000 pigs or 2,000 cattle.

Two weeks ago, MEPs voted to cut funding for farms that exceed a certain stocking density and for new rules saying farm animals must be able to lie down, stand up, extend their limbs and turn around.

The environment committee also voted to block national subsidies for large facilities not respecting basic animal-welfare principles.

The agriculture committee will vote on the plans next month.

It came as a Greenpeace study revealed that more than 71 per cent of EU farmland is used to feed livestock.

The research said up to €​32bn (£27.5bn) in agricultural subsidy payments were encouraging industrialised farming.

According to Eurostat, nearly three-quarters of European meat and dairy products come from the largest farms.

Greenpeace EU agriculture head Marco Contiero said: “Factory farms wreck the countryside, heat the climate and put small farmers out of business, but MEPs put forward some solid plans that could start to change that.

“Study after study shows the immense damage factory farming does, so Europe’s agricultural system must evolve.”

The European Commission and EU farmers’ group Copa Cogeca dismissed the report, saying it was not based on facts or statistics.

In the UK, residents are fighting proposals for new large-scale farms. Opponents of a mega-egg farm with 112,000 chickens in Cornwall are crowdfunding their campaign.

Three 130-metre sheds would house 32,000 birds each and a fourth would have 16,000.

Government must also introduce measures including a tax on meat Matthew Glover

The food company behind the scheme says the hens would be free-range.

In Pembrokeshire, at least 25,000 people have objected to plans for a “free-range egg-laying unit” for 64,000 hens.

Matthew Glover, head of Million Dollar Vegan, which shot the footage, said: “If we want to get to grips with the environmental crisis and end cruel factory farming, there must be an immediate end to planning permission for mega-farms.

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“Government must also introduce multiple measures, including a tax on meat, that will reduce both consumption and production of animal products.”