More than 65 per cent of passenger-carrying vehicles stopped by traffic police in Oxfordshire during a summer crackdown were found to be operating illegally.
In all, 91 vehicles, including coaches, buses and limousines were stopped across Oxfordshire, Berkshire and Buckinghamshire in the one-day Operation Tourist check.
Of these, 34 per cent were found to be breaking the law.
In Oxfordshire, officers stopped 15 vehicles on the M40 in Cherwell Valley - ten of which were found to have problems.
Two of these were found to have serious defects and the drivers were issued with prohibition notices banning them from travelling on in those vehicles. Another was given a delayed prohibition notice, requiring the driver to take it away and have it fixed.
Three other cars were found to have tachograph irregularities and four drivers were cautioned for minor offences.
Those stopped by traffic officers across the region included a ten-seater stretch limousine en-route to pick up a bride.
It was carrying 14 people but had no operator's licence and no passenger-carrying vehicle licence.
Insp Dave Hartin, head of the Thames Valley Police Traffic Intelligence and Operations Unit, said: "The fact that more than one third of all the vehicles stopped by our officers were defective or operating illegally, shows the value of these checks."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article