UK car sales plummeted by over a fifth last month.

New data from the Society of Motor Manufacturers and Traders revealed the number of new vehicles registered was down by 20.5 percent.

“September’s large decline follows an unusually high August and a turbulent first eight months of the year as the market responded to a raft of upheavals, from confusion over diesel policy to VED changes and, latterly, transition to the new WLTP emissions standards,” said the SMMT.

Mike Hawes, the group’s chief executive has said that car sales across Europe have been hit by the new emissions tests.

“With the industry given barely a year to reapprove the entire European model line-up, it’s no surprise that we’ve seen bottlenecks and a squeeze on supply. These are exceptional circumstances with similar declines seen in other major European markets,” he said.

“The good news is that, as backlogs ease, consumers and businesses can look forward to a raft of exciting high-tech cars and a market keen to recover lost momentum.”

The figures have also revealed Volkswagen (ETR: VOW) sales to have plunged by 55 percent. VW sold 16,283 cars last month, which is down from 36,332 a year earlier.

As the results have been released, carmaker Nissan (TYO: 7201) has also warned of the “serious implications” that would follow a no-deal Brexit.

“Today we are among those companies with major investments in the UK who are still waiting for clarity on what the future trading relationship between the UK and the EU will look like,” said Nissan.

“As a sudden change from those rules to the rules of the WTO will have serious implications for British industry, we urge UK and EU negotiators to work collaboratively towards an orderly balanced Brexit that will continue to encourage mutually beneficial trade.”

Many car manufacturers have warned about the consequences of a no-deal Brexit including BMW (ETR: BMW) and Jaguar Land Rover.