David Cameron has visited the most Eurosceptic region in the UK in an attempt to convince voters there to opt to remain in the European Union.
A Sky Data study shows that East Anglia is the most Eurosceptic region in Britain, with London holding all of the country's top 20 pro-EU districts.
The top five districts with the highest proportion of Leave supporters are in East Anglia - with Tendring, home to the UKIP stronghold of Clacton, coming first on the list.
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During a visit to Felixstowe on Tuesday to mark 100 days until the referendum, Mr Cameron said he had seen the poll but attempted to change minds saying that East Anglia benefited greatly from the UK's membership of the EU.
He said it was important to the British farmers and the 39,000 people in the area working in agriculture and those in jobs linked to trade, and he said the area benefited from financial support for community development.
Mr Cameron said: "British farmers know today that we have got open markets right across Europe: a market of 500m people, no quotas, no tariffs, no restrictions and I think that is a huge advantage for our farmers."
Coastal areas dominate the top 30 pro-Brexit zones, including North Norfolk, Dover, Torbay, the Isle of Wight, Weymouth and Portland, Thanet, Gosport and Cornwall.
The capital's core of Westminster, Kensington and Chelsea, and the City of London make up the top three districts with residents most likely to vote to remain in the European Union.
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In many pro-Brexit areas, agriculture is the biggest industry - and because the EU accounts for more than half of all British food exports, there are more jobs linked to EU trade in these regions, per head of the population, than in London.
But in Fenland, the second-most Eurosceptic district, British-born residents complain about who gains such employment.
Unemployed Gareth Sweet, a 20-year-old from Wisbech, told Sky News: "All the jobs go to Eastern Europeans. I turned up at one factory and everyone said 'What are you doing working? You are British.'"
Wisbech Town Council estimates that 35% of its population are immigrants.
But one farmer who didn't want to be identified said: "British workers aren't prepared to do the backbreaking work like pulling turnips out of the ground.
"Personally, I don't like the EU, but without the EU subsidy it wouldn't be worth me planting any crops, I'd make a loss."
The Sky data is calculated by looking at the demographics of each region and the numbers who fall in to categories most likely to vote to leave the EU, such as older retired people or younger people struggling to find work.
However, areas that lean towards an Out vote also appear to correlate with high migration figures.
Between 1995 and 2014, there has been an increase of 4 million foreign-born people living in the UK, according to the Migration Observatory.
Over that period in the east of England, there was an increase of 122%.
But for the least Eurosceptic region in Britain, inner London, there was a smaller proportional increase of 68%.
There are still many in the East Anglia who wish to remain in the EU.
Mustard farmer Michael Sly told Sky News: "The EU has given us stability over the last 40 years in agricultural markets.
"Over 70% of our exported food goes to the EU, and particularly for lamb and beef it is crucial. It has been a very positive partnership."