2 July 2012 Last updated at 07:52 ET

Defects found on buses taking pupils to Blair Drummond Safari Park

Nine buses being used to take school pupils to a safari park were taken off the road after police found serious mechanical defects on the vehicles.

The discovery was made during checks at Blair Drummond Safari Park, near Stirling, between 18 and 22 June.

The most serious defect was an emergency door which would not shut.

The buses were checked while the pupils were inside the safari park. Alternative transport had to be provided to get the children home.

The joint operation by Central Scotland Police and the Vehicle and Operator Services Agency (Vosa) also found a faulty exhaust, oil leaks and a broken seat belt.

Fifteen drivers were also found to be working in excess of their hours or unable to prove the hours they had worked, and were not allowed to drive until they had had a sufficient rest period.

Sgt Bob Murphy said: "The buses were checked while pupils were inside the safari park and those with the serious defects were immediately taken off the road.

"The operators then had to find alternative buses to collect the pupils once their visit was over."

He added: "Bus companies are given the responsibility of safely taking pupils to and from school and on school outings.

"It is extremely worrying that nine buses were so defective they had to be removed from the road with immediate effect.

"We want to reassure parents that we will do everything we can, along with Vosa, to make sure their children are travelling on buses that are completely roadworthy. We will continue to address this."