John Hamill, 65, completed his order on Thursday, only to be handed an invoice with a stamp that said the price could change any time up to delivery day, should a customs duty tariff be put on cars imported into the UK after leaving the EU.

The retired company director, from Hamilton in Scotland, was not told the cost could change prior to putting down a £500 deposit.

He says staff were also unable to give him a firm date of delivery, meaning he could be waiting until May to know the final price.

John told Metro.co.uk: ‘I ordered the car, I paid the £500 deposit and then they handed me the invoice – and that’s when I found out the price I’ll finally be paying is actually unknown. You couldn’t miss the big stamp.

‘You would think they’d tell me this before, but they didn’t.’

He added: ‘They couldn’t give me an estimate of how much the price could go up by because they don’t know what’s happening.’

‘Normally it would be delivered at the end of March. They’re saying it could be April or May.

‘So not only do we not know the price, we don’t know the delivery day. They’d usually be able to tell you but they can’t even do that.’

However, John believes his car is the tip of the iceberg when it comes to ‘Brexit surprises’.

He said: ‘I was not very happy when I ordered the car. But in the grand scheme of things, it’s just one small thing and how many other things are happening that we don’t know about? Things that are much more serious.’

‘I think the slogan “Get Brexit Done” was very simplistic but the reality will prove something more difficult.’

‘People don’t know these things. I’ve watched the Brexit debates happen over about three and a bit years.

‘I’ve been paying attention to everything that’s happened, but they basically tell you nothing.

‘The government isn’t disclosing exactly what’s happening. It’s only when things like these turn up that you actually find out.’

Mercedes-Benz is likely to not be the only car manufacturer looking to protect profit margins by putting pricing disclaimers on cars as the UK prepares for Brexit.

This month, the UK’s car industry body called on Boris Johnson to secure a frictionless, tariff-free trade deal with the EU which avoids barriers for businesses.

In a statement, Society of Motor Manufacturers and Traders CEO Mike Hawes said: ‘UK car production is export-led, so we look forward to working with the new government to deliver an ambitious trade deal with the EU.

‘That deal needs to be tariff-free and avoid barriers to trade, which, for automotive, means that our standards must be aligned.’

A spokesperson from Mercedes-Benz told Metro.co.uk: ‘The information on Mr Hamill’s order form is to notify customers that should a customs duty tariff become applicable on cars imported into the UK after leaving the EU, we will review our pricing to adapt to the changed circumstances.’