An Apache helicopter came within 150ft of colliding with an air ambulance while taking off from Wattisham Airbase.

The two aircraft were travelling at more than 100mph over Suffolk when the near-miss took place in May.

A report on the incident has been released by Airprox, an organisation which looks into the circumstances surrounding near-misses in Britain’s airspace.

It revealed the pilot of the Apache was setting off from the army airbase base shortly after 4pm before seeing the helicopter emergency medical service (HEMS) travelling overhead.

The pilot believed that the two aircraft came within 150ft of each other and described the collision risk as “high”.

The Apache was travelling at 100knots, the equivalent to 115mph at the time of the incident.

Air ambulance crew members, who were travelling from Cambridgeshire to Ipswich on an emergency call, confirmed their aircraft was going at 120knots or 138mph.

The pilot from the HEMS aircraft could see the other helicopter as it left Wattisham Airbase from just over a mile away and decided to maintain altitude and track the progress of the other aircraft.

He said that the two helicopters passed within 300ft of each other but described the risk as “low”.

On arriving in Ipswich, the pilot discussed the events with a colleague and said he was “surprised” that the Apache had been cleared for take off while they were in the immediate area.

Concluding the report, the Airprox board put the near miss down to “combination” of aspects.

They described the situational awareness and action taken by the air traffic controller as “ineffective”.

They also said the regulations, processes, procedures and compliances were not completely complied with, as the Apache crew did not give way to the EC145 converging from the right - but closed to a range at which avoiding action was required.

The degree of risk of a collision was given as C, the third highest grade, and no further recommendations were made.

This is not the first time that defence aircraft from Suffolk have been involved in near misses.

In October last year, two F-15 fighter jets nearly collided at more than 350mph on their way back to RAF Lakenheath.