16 out of 36 air ambulances in the UK have been grounded as a result of a suspected fault. Bond Air Services, which leases the aircraft to the individual emergency services, said it has suspended flying of all its Eurocopter EC135 helicopters across the UK.

The helicopter is the same model as the one that crashed on to a pub roof in Glasgow nearly two weeks ago, killing 10 people.

The tenth, named as 59-year-old Joe Cusker died on Thursday afternoon.

All the air ambulances grounded are operated by Bond, which has also grounded another six helicopters. It is thought that some of the other six could be police helicopters.

It is understood that military helicopters are being drafted in to cover the grounded air ambulances in Scotland.

The helicopter's manufacterer Eurocopter says there are a total of 20 EC135s used as air ambulances and another 20 used as police helicopters in the UK. In total there are 57 aircraft in the UK.

Experts said is normal in this situation for other operators to follow Bond and ground their EC135s as well. Bond said it made the decision after a problem with a fuel gauge on another of its EC135s on Wednesday.

Chopper experienced "indication defect"

A statement put out by Bond Air Services on Thursday said: "During normal operations yesterday, one of our EC135 fleet has experienced an indication defect that requires further technical investigation".

"Therefore as a precautionary measure we have temporarily suspended service operations whilst we undertake detailed diagnosis. We commenced investigations overnight, are continuing this morning and are in close liaison with Eurocopter regarding this investigation.

"We continue to investigate the technical fault that resulted in us temporarily suspending service operations yesterday.

"We are now conducting functional tests across each of our EC135 aircraft in order to gather more specific information."

The Association of Air Ambulances have said a number of air ambulances are grounded at any one time and it is normal that helicopters from other areas cover the regions where that happens.

The grounding comes on the day when the youngest and oldest victims of the Clutha helicopter crash have been laid to rest at separate funerals. Colin Gibson (33) and Robert Jenkins (61) were among those killed when an EC135 crashed on to the roof of the Clutha pub.

Aviation expert Paul Beaver says the cause of the Glasgow crash still is not known.