WHAT is a customs union, what does it mean to leave it as part of Brexit and how does this matter to ordinary people?

These are some of questions I, as part of a delegation of MPs and Lords, explored in a two-day session at the European Parliament this week.

The customs union is the mechanism by which goods and services can cross the UK/ EU border without delays, costly paperwork or tariffs: when a lorry coming from another EU country gets to our border, it passes straight through. This ease of transport is crucial to manufacturers who maximise efficiency by using a model called ‘just in time’, where parts are carefully sequenced to ensure they are installed within hours of arriving at the plant. This cuts costs as you don’t have to worry about storing them.

This is the way one of our main local employers, BMW, operates. In a meeting with them last week, they explained how their complex supply chain relies on components criss-crossing our border numerous times. For example, the crankshaft used in a Mini crosses the border three times before it is installed in Oxford. They do this because the materials, skills and expertise needed at each stage of the design and manufacture are better found in different places, and it makes sense as transporting the part between factories is seamless.

Come out of the customs union and this is all much more difficult. Lorries risk being held up at the Eurotunnel and that ‘just in time’ model becomes less certain. To mitigate, BMW may need to acquire warehouses to store parts and ensure there is no break in the assembly line. Then there is the paperwork that would be an inevitable, and that will need manpower. All of these things add cost, making the UK legs of the journey much more expensive. By leaving the customs union we are essentially putting jobs at risk if the Oxford plant can’t keep its competitiveness.

That’s what has me so worried: people’s jobs are at risk. To imagine we will have a frictionless border is a bit of a pipe dream according to the officials I met. It’s true that Turkey has a customs union with the EU, but it is not the same and goods are subject to checks. The fact is, for any pan-European manufacturing business, of which we have several in Oxfordshire, there is no better deal than the one we currently have. If costs rise they have a choice – raise prices (which hurts the consumer), or move the jobs to other countries. Either way, our local economy is hurt.

That is why I am passionate about us staying in the customs union – whatever one may think of Brexit.