A ship's captain was emotionally distressed when his vessel collided with a North Sea oil platform, a tribunal heard.

The Forties Echo platform was evacuated after the incident with the Sea Falcon offshore tug on March 16, 2015.

Apache, which operates numerous installations off the coast of Scotland, was handed an improvement notice by the Health and Safety Executive (HSE).

It ordered the firm to make significant changes to the way it monitors marine traffic within a 500-metre radius "safety zone" of the platform.

The firm is now appealing the notice, insisting staff took the appropriate action to reduce risk to its employees and the vessel's crew.

At a tribunal held in Aberdeen on Wednesday, Apache's legal representative, solicitor Peter Gray, argued it was the responsibility of the crew to make sure it was operated safely.

He said the master of the vessel was under "emotional distress" at the time of the accident because he had received bad news of a family member by email before he took control of the vessel.

Mr Gray asked Alan Pemberton, a specialist inspector from the HSE who was involved in the investigation, if he was aware of factors leading up to the collision.

He replied: "I was aware of an issue with the master being distressed, perhaps because of the bad news he had received.

"Clearly that was perhaps something the installation was not made aware of. One question was whether he should have continued what he was doing, I don't know."

Mr Pemberton suggested oil platform staff should have been monitoring the ship to make sure it was being operated according to safe zone guidance.

He said: "Certainly in the early stages, if they had been monitoring right at the onset and saw what was going on, then maybe if they had been doing that they could have contacted the vessel and challenged what the vessel was doing, which may have refocused the master's mind."

The tribunal continues.