Both sides of the debate have clashed on Premier's News Hour ahead of the referendum on Britain's membership of the European Union.
On Thursday, voters will be asked the question: "Should the United Kingdom remain a member of the European Union or leave the European Union?"
Polls suggest the result is too close to call and the campaigns to leave and remain in the EU are neck and neck.
Opening Premier's News Hour debate on immigration, Leave campaigner, UKIP MEP and Christian Jonathan Arnott, said free movement of people in the EU meant there was a "free for all".
He said: "I'm not saying that immigration is a bad thing; controlled immigration is a good thing.
"If you started with a blank piece of paper you would never, ever, in a million years, devise the system that we've got now."
For the remain campaign, Baroness Sal Brinton, President of the Liberal Democrats, said the NHS could "not manage without immigrants".
She added: "It's absolutely vital for our country that [immigration] continues.
"Often people from the EU are filling jobs that British people will not take.
"Talk to any farmer. None of our farmers could operate without local agricultural workers."
Challenged on where Britain's Christian heritage would be best served, in or out of the EU, both guests referred to the Parable of the Good Samaritan in their arguments.
Baroness Brinton said the union brings unity and ensures outsiders are welcomed in: "If you think about the parable of the Samaritan, that's an outsider.
"The definition of neighbour that he took included people who are not part of our immediate communities.
"As Christians, we have a role to lead the way in championing these values internationally.
Jonathan Arnott replied: "I would have used exactly the same passage, but I would have said when we speak of our neighbour, we're not speaking just of our local community, our community within the United Kingdom, or indeed our European community, and I would say that actually what we need to do is see the whole world as our neighbour."
He added people would be better off if the country votes to leave and urged Premier Radio listeners to ignore scaremongering: "Let's remember that these are precisely the same threats which were made if the UK didn't join the Euro, and that worked out in completely a different way.
"We pay out to the EU more in membership contributions than we get back, something in the order of nine to ten billion pounds a year."
But Baroness Brinton said she had spoken to one man who was very worried about a leave vote: "His job entirely depends on us remaining within the EU.
"He knows that Frankfurt are just waiting for us to leave to take a lot of the work from the City of London.
"The knock-on effect of one of our most profitable bits of business will happen throughout our society."
Baroness Brinton warned a Brexit would impact the country's trade: "Why on earth would Europe want us to leave the club and then expect exactly the rest rates and services as we had when we were in the club? Of course it is going to cost us."
But Jonathan Arnott said: "We would remain the world's fifth largest economy. We would remain committed to organisations like Interpol, G7, G20 [and] the United Nations Security Council and so on. So, we continue our global perspective. We continue to trade freely with the European Union."
Polls open across the UK at 7am on Thursday and close at 10pm. The result should be known on Friday morning.
Listen back to the full Premier's News Hour debate by clicking here.
