Iain Duncan Smith has claimed it is “ridiculous” to “go on about” job losses feared to happen under a no-deal Brexit. 

The ex-work and pensions secretary said during an LBC interview on Saturday “not a single job will be lost” should Britain crash out of the EU without a deal on March 29. 

“I think this is all complete nonsense,” he said, when questioned about the risks of the UK failing to secure any agreement with Brussels.

And in an interview with BBC Radio 4′s World At One on Monday, Duncan Smith doubled down on the claim, saying “there will be lots of opportunities”. 

He added: “I’m talking about overall; what’s the short-term and what’s the medium term.

“We will create more jobs. It is ridiculous to go on about the jobs issue.” 

It came as car manufacturers warned of an “existential threat” of a no-deal Brexit to industry and urged the prime minister to agree a transition period with Brussels. 

“It’s still hard to see any upside to Brexit,” said the Society of Motor Manufacturers and Traders (SMMT) chief executive Mike Hawes.

“Everyone recognises that Brexit is an existential threat to the UK automotive industry and we hope a practical solution will prevail.” 

But during the same interview, Duncan Smith said the government could refund car manufacturers tariffs they will be forced to pay under no-deal.

The former Tory leader went on to insist World Trade Organisation rules would allow the UK and EU to “move immediately to zero tariffs” while negotiating a free trade deal post-exit day. 

The UK would face punishing 10% tariffs on car parts should it drop into WTO rules, but Duncan Smith claimed UK “taxpayers are paying extra £5bn to give companies the right to have a free export into the EU” as it stands. 

He added: “What the government can do straight away is to take the extra money we don’t pay into the EU and make sure that they then essentially give back to those companies if necessary that cost.” 

British new car sales in 2018 fell at their fastest rate since the global financial crisis a decade ago, it also emerged on Monday.

Manufacturers have been hit by the collapse in demand for diesel, as well as by a Brexit slump. 

Registrations dropped 6.8 % last year to 2.37 million vehicles, the largest fall since sales nosedived 11.3% in 2008, according to the SMMT.

A near-30% drop in demand for diesel was said to be the most significant factor in the decline.

Birmingham Erdington MP Jack Dromey, whose constituency encompasses the Castle Bromwich Jaguar Land Rover (JLR) plant, called Duncan Smith’s claims “fanciful”.  

He said: “JLR doubled in size from 2010 and it has now lost 3,000 jobs. 

“And for me that really matters, because these are people whose lives were transformed by the success of JLR and what we have heard from Iain today is absolutely typical of the wide-eyed Brexiteers who are oblivious to the consequences of their actions and that is why we have to rule out a no-deal Brexit.”