Not the most reliable source of information, but probably factually correct in this instance.
These paragraphs are the most relevant (my italics):
"Drivers could face the hefty penalty if they put their car in for an early MOT before their previous certificate runs out.
Vehicles will no longer be road legal if they fail the test – even if the old certificate is still valid.
Drivers who hit the roads could be slapped with a maximum £2,500 fine, a driving ban and three penalty points under the new rules coming into force next month.
Tougher diesel tests, extra major failure categories and new lighting tests will also be added on May 20."