On Monday, UKIP launched its immigration policy for the forthcoming general election.

Over the past few months, UKIP have spoken out that they are the party of low immigration, a position they want and need to retain. There is no doubt that since UKIP rose to national relevance, they have pushed the immigration debate to the frontline of UK politics.

However, if they want to continue to be seen as the party of low immigration, their policy announcement yesterday certainly didn’t show it. I call it a ‘policy’, but I say that lightly – it seemed more like a headline, than a well-thought out policy proposal.

UKIP wants to end mass migration. There is nothing wrong with their objective, but their proposals on the other hand, are simply confusing and unworkable for government.

The Brexit vote last year has thrown the immigration debate wide open. It has left no stone unturned with absolutely nothing off limits for discussion.

The only way the debate moves forward and progresses is with legitimate policy solutions that are workable in practice. I don’t think UKIP’s new immigration policy delivers this, hence my disappointment. I certainly don’t write this from spite, but from a position of moving the immigration debate forward.

Immigration is a complex issue – that there is no doubt. The way that those who want to see migration reduced significantly, including myself, win the argument and policy agenda is by putting forward research-based solutions to tackle those complexities.

I’ve seen very little detail around Monday’s proposal that fills me with any great confidence.

I’m still none the wiser how their policy of ‘one in, one out’ will actually work in practice. Will this particular policy be enforced literally? If so, I have no clue how government machinery can possibly cope with such a policy. While that sort of system works for when car parks are full, I’m not sure how it can possibly work for a country, dealing with hundreds of thousands of people over various entry and exits points.

But the biggest flaw is in the numbers – I can see little detail to what areas of migration they are proposing to cut.

They are seeking to control and cut work with a 5-year freeze on unskilled labour, which I support, but I see little detail on how they plan to control Tier 1 and Tier 2 immigration.

If my sums add up, with an aim of ‘balanced migration’ (a net number of zero), their plan will only allow for 17,000 workers to come into the UK, if they make no changes to other categories of immigration.

Stay with me as I go through the numbers. My calculations show: emigration of 323,000 in the year ending September 2016. Looking at the Long Term data set from the ONS numbers, immigration (those that entered) stood at 304,000 per year excluding those on a work visa. This includes the following categories: Students: 174,000; Family Reunion: 74,000; ‘No reason stated’: 35,000 and a catchall group including asylum: 61,000.

Yes, family reunion would be reduced by reducing work migration, but the number of Tier 1 and Tier 2 workers allowed to come to the UK under this policy would be considerably less than what it is today (around 100,000). Note that this refers to non-EU applications, as we’re still members of the EU.

If this presumption is correct then this policy would be incredibly damaging for business and industry… and I say this as someone who is against mass migration and has proposed a plan to reduce levels to around net 50,000 per year.

If UKIP want to maintain a healthy number of skilled workers entering the UK and reach their net zero number, they will have to cut back on areas such as asylum and students.

As the debate continues post Brexit, the question is not whether migration canbe reduced to the tens of thousands as proposed by the last Conservative government – the question is how and why.

Those that say it can’t are wrong. They say it can’t but in reality, they just don’t want it to reduce to that level.

After Brexit, with the changes I set out a month ago, net migration can come down considerably – into the tens of thousands by freezing unskilled labour, but limiting the number of Tier 2 visas granted per year to 100,000.

The way UKIP stays the party of low immigration is by being credible. It gains credibility by producing policy-led solutions.