A month before Brexit we were filming in St Ives, a Cornish town that might best be described as a better-heeled version of Byron Bay.

"Vox pops" were hard to find.

Many people were simply too embarrassed to publicly declare they were voting out.

"I don't like [UKIP leader Nigel] Farage but he's got a point", explained one elderly man, who asked to remain anonymous.

"The major parties aren't addressing immigration. Why should we remain in?"

A few weeks later we were in working class Leeds, the other end of the country and social spectrum, yet the sentiment was surprisingly similar.

"I don't want to say it loudly but I'm out", whispered one woman with a baby on her hip.

"With all the new people, there ain't many jobs and I just can't see a good reason to stay."

There are a variety of theories as to why Britons ultimately backed Brexit.

They're all being fleshed out now over the sleepy weeks of summer by shocked commentators and pundits, who are still trying to work out how they got this campaign so badly wrong.

Some blame Labour leader Jeremy Corbyn for not doing enough, others accuse the Leave side of lying its way to victory.

But as an outsider, I found the lack of a coherent Remain campaign on immigration startling.

Remain camp lacked passion, coherence

It was probably the biggest issue, yet when politicians, media pundits or punters raised concerns about EU migrants or asylum seekers, they were often labelled racists, shouted down or the topic was changed to the economy.

There was a split between generations with young voters overwhelmingly voting Remain. ( AFP: Geoff Caddick, file )

Few Remain figures passionately and articulately argued for immigration and free movement until the last fortnight of the campaign.

Perhaps this was because so few people thought Leave would win but it meant the public anxiety about migrants wasn't addressed head-on.

Many wavering voters waited in relative silence before turning out in big numbers on polling day.

Leave EU strategists, who caused controversy with the "breaking point" asylum seeker poster, believe they got stronger every time they were attacked, or derided, because although people were offended by some of their tactics the "basic underlying argument" about migrants struck a chord and was rarely challenged.

So, would a different Remain campaign on immigration have changed the result?

Maybe not.

The outcome was influenced by a vast array of factors, not least that both sides of British politics have blamed the EU both fairly, and unfairly, for a variety of problems over several decades.

Even before the campaign started, the Leave camp was on fertile ground.

Lesson: Don't mock anti-immigration groups

But if there is a lesson in Brexit for Australia's political class, it's probably that the concerns of anti-immigration groups, like One Nation, shouldn't be simply mocked, ridiculed or ignored.

One Nation has four senators.

In comparison, UKIP, which former UK prime minister David Cameron once described as a bunch of "fruitcakes, loonies and closet racists", has just one representative in the House of Commons and three in the Lords — it also has 22 members in the EU Parliament.

Yet the party's long running campaign played a major role in getting 52 per cent of voters to remove Britain from the EU.

During the UK referendum campaign Australia's points based immigration system was put on a pedestal.

Brexiteers, particularly Mr Farage and Foreign Minister Boris Johnson, lauded its ability to attract skilled workers and integrate new arrivals into society.

At home however, the relative economic and social success of the bipartisan program is often overlooked.

If One Nation is to be vanquished, a goal both major political parties have, then Australia's leaders could do worse than looking back at Brexit and fostering frank, fearless public debate.