Tractors gather at Parliament in farmer go-slow protest
More than 100 tractors have rolled past the Houses of Parliament as farmers protested against what they say is a lack of support for UK food production.
Convoys with horns blaring made their way through central London's streets to Westminster on Monday evening.
Organisers Save British Farming and Fairness for Farmers of Kent said cheap food imports and unsupportive policies were putting UK food security at risk.
The government said it put farming "at the heart of British trade".
Tractors flying Union flags made their way across London and through Westminster, carrying signs with slogans such as 'Save British farming' and 'No farming, no food, no future'.
"I'm a third generation farmer. I'm here for my future," Ben Stickland, 21, from West Sussex, told BBC News. "There are multiple nails being put into this coffin built around us."
The protest comes as months of heated demonstrations in Europe, including blockades, saw angry farmers in Greece, Germany, Portugal, Poland and France demonstrating against European Union regulations and cheap imports.
Thousands of farmers also joined forces in Wales to fight new farm subsidy plans launched by its government.
There have previously been a handful of demonstrations in England, including in Kent and Cornwall, but Monday's tractor rally was the largest so far.
Another farmer attending the rally is Colin Rayner, who has 2,000 acres of arable land across east Berkshire and south Buckinghamshire.
He told the BBC that he had "no choice" but to protest, saying that business was so bad that "this could be our last harvest".
"We have been, as most farmers have been, living in our overdraft now for the last five years.
"We can't see it getting any better - yields have plateaued, prices are dismal, our costs for raw materials are horrendous and the regulations that we have everyday are mindboggling," he explained.
Mr Rayner said the environmental focus of the government's farm payments scheme, which replaced EU subsidies, was coming at the expense of domestic food production while cheap imports were being produced to lower standards.
"We have been farming for 500 years and the government now has a scheme where they will pay us more money to grow wildflowers than to grow food. It is insanity," he said.
"They want us to rewild the countryside. I just ask how are they going to feed the people living in the towns?
"We have got to have food from our own resources. We have got to produce healthy good food - which we can do."
In England, campaigners say government agricultural policy and its Environmental Land Management farm payments scheme, together with weak trade deals, "non-existent" import controls and misleading labelling, have all served to undermine farming businesses.
They say that threatens the country's ability to produce enough food to feed its own population, "leaving our food security in peril".
Founder of campaign group Save British Farming Liz Webster said: "Farming is fraught with risks: risks that have intensified every year with the climate emergency, Ukraine war and Brexit reality, which have only served to exacerbate problems.
"Polling shows that the public back British farming and food and want to maintain our high food standards and support local producers.
"We need a radical change of policy and an urgent exit from these appalling trade deals which will decimate British food."
At last month's NFU conference, the Prime Minister Rishi Sunak told farmers "I've got your back," as he outlined government plans to boost the UK's food security.
It was a promise echoed by farming minister Mark Spencer on Monday, who said: "We firmly back our farmers.
"British farming is at the heart of British trade, and we put agriculture at the forefront of any deals we negotiate, prioritising new export opportunities, protecting UK food standards and removing market access barriers."
Mr Spencer also announced new measures that would limit the amount of land that could be taken out of production and put into specific environmental schemes.
The change means that under the Sustainable Farming Incentive (SFI) payment scheme farmers will only be able to put 25% of their land into projects that would take it out of direct food production.
"Food production is the primary purpose of farming and today we are taking action to clarify this principle," said Mr Spencer.
The government said that at least 60% of the food we consume will continue to be produced here in the UK and that level of food security will be monitored each year.
It says it has maintained the £2.4bn farming budget and was also looking at ways to improve fairness in the supply chain.
It has also launched a consultation on fairer food labelling regulations.