Starting today

Now bringing in stricter rules for diesel car emissions with a diesel particulate filter (DPF), which captures and stores exhaust soot to reduce emissions from diesel cars.
There are also new tests in the updated MOT including under-inflated tyres, contaminated brake fluid, brake pads missing or defective warning lights, dashboard monitoring and fluid leaks posing an environmental risk.
A car will fail if smoke of any colour can be seen coming from the exhaust or there is evidence that the DPF has been tampered with.

Also new categories of test result

What the new categories mean:
Dangerous A direct and immediate risk to road safety or has a serious impact on the environment. Do not drive the vehicle until it’s been repaired. Result: Immediate fail
Major It may affect the vehicle’s safety, put other road users at risk or have an impact on the environment. Repair it immediately. Result: Immediate fail

Minor No significant effect on the safety of the vehicle or impact on the environment. Repair as soon as possible. Result: Pass
Advisory It could become more serious in the future. Monitor and repair it if necessary. Result: Pass
Pass It meets the minimum legal standard. Make sure it continues to meet the standard. Result: Pass

Cars over 40 years old are now exempt though.

https://www.yorkshireeveningpost.co....151603352fc39/