About 25 kilometres out of Tamworth is a billboard.

At first glance, it looks like another one of Tony Windsor's election signs; it has exactly the same colours, and exactly the same design. There is even a big photo of Mr Windsor smiling with former prime minister Julia Gillard.

And that is the giveaway. It is in fact a clever, and sophisticated attack ad.

Above the words "Not This Time, Tony" are reminders of the perceived sins of the Labor government he anointed in 2010 — the carbon tax, deaths at sea, and the ban on live cattle exports.

What does Mr Windsor think of it?

"It tells me they're worried," he says.

They are certainly taking it seriously.

When Mr Windsor retired at the 2013 election, he effectively handed New England to the National Party's Barnaby Joyce, who won with a comfortable margin of almost 20 per cent.

The Nationals had held New England for nearly 80 years before Mr Windsor took it off them. With him off the scene, the party could well have assumed another dynasty was beginning.

But then, in March, Mr Windsor announced he was coming back.

Mr Joyce was not surprised.

"I suspected all the way through," he says.

"I've been in this game a long time. When he went with Labor, I could say 'I knew which way you were going to go'. When he was going to come back, I said, 'yep, I knew that'.

"So it wasn't a surprise at all."

Windsor capable of snatching seat from Joyce

Mr Windsor is probably the only person who could take this seat away from Mr Joyce.

When he held New England, his huge personal following made it one of the safest seats in the country.

Former National Party leader John Anderson says Barnaby Joyce could lose. ( Four Corners )

At his last election in 2010, Mr Windsor pulled more than 70 per cent of primary votes in New England's biggest city, Tamworth.

In the second-biggest, the university town of Armidale, it was nearly 80 per cent.

John Anderson is a former National Party leader and deputy prime minister. He was Mr Joyce's campaign director in 2013 and says the Deputy PM could lose this election.

"He will need an unbelievably strong primary vote in his own right. If he doesn't get it, the way the preference gaming goes on these days, he could lose it," Mr Anderson says.

"He'll have to be very high 40s in order to pull this off."

Gloves off in polarised electorate

Labor and the Greens are giving Mr Windsor their first or second preference and putting Mr Joyce at the bottom of the ballot.

Other independents are not issuing how-to-vote cards, but given that several are standing on issues like climate change, and against coal mining on farming land, their preferences are largely expected to flow to Mr Windsor.

The acrimony between Mr Windsor and the National Party is long and deep.

Mr Windsor and Mr Anderson have had a particularly bitter relationship, although Mr Anderson says he has apologised for his part in it.

Tony Windsor announced he was going to contest New England in March. ( Four Corners )

The relationship between Mr Windsor and Mr Joyce is not much better.

The electorate appears polarised as well. It is hard to find a swinging voter.

It will not be easy for Mr Windsor. First of all, Mr Joyce this year became the leader of the National Party, and with it, assumed the title of Deputy Prime Minister.

With the Coalition favourites to win the election, Mr Joyce has a powerful pitch to voters — having their local member at the top of the Cabinet table.

"I just think that a lot of people are sitting back quietly and having consideration for what's going to happen in the future," he says.

"And who's going to be able to be the best outcome for them in the future. And also who's going to put their nation in the strongest position."

But Mr Windsor says having the Deputy PM as a local member has not done other electorates much good in the past.

"Warren Truss left his seat the poorest regional seat in Australia," he says.

"Mark Vaile, when he left, they regarded him so highly they voted in an independent in Rob Oakeshott. And John Anderson, when he left, the seat was abolished because it had lost so much population."

Joyce, Windsor face personal hurdles

Two weeks ago, Mr Joyce faced a grilling from the audience on the ABC's Q&A program in Tamworth, asking why he was unable to stop projects like the Shenhua Watermark coal mine from going ahead on the rich farmland of the Liverpool Plains.

Mr Joyce himself describes the project as "madness" — but says it is a state issue, that the Commonwealth is powerless to stop.

Barnaby Joyce won New England with a comfortable margin of almost 20 per cent in 2013. ( Four Corners )

But the biggest hurdle for Mr Windsor in this campaign is the decision he took in 2010.

In the hung parliament, he decided, along with fellow independent Rob Oakeshott, to support Ms Gillard over Mr Abbott.

There is no doubt it has cost him some of the massive personal following he held before, from people who themselves felt betrayed.

The question that will be answered in election day is — how much?