A police veteran was fined by armed officers for "parking" in a bus stop for less than a minute.

Our sister paper the Herald reports that the Retired superintendent Jim Kirkwood received the £30 fixed penalty after pulling up next to a marked patrol car to ask his former colleagues for directions outside Prestwick Airport.

The 60-year-old - whose 30-year police career included a stint in senior positions in the Special Branch of the old Strathclyde force - believes the episode underlines long-standing concerns that officers are losing their powers of discretion.

Deeply disturbed by the incident, he has fired off complaints to both the new Police Scotland and its watchdog, the Police Investigations and Review Commissioner (PIRC), but to no avail.

Mr Kirkwood paid the fixed-penalty fine, a move which effectively means he admitted guilty in the eyes of the law. But he believes officers should have used their discretion to realise he had made what is a common innocent mistake at the airport.

Mr Kirkwood said: "Discretion is one of the most powerful weapons that a police officer has. But I feel this power has been eroded in this new culture of targets."

The retired officer - who lives in East Ayrshire - formally complained that the two officers had issued his fine with "undue haste" and acted with "inconsiderate or unreasonable conduct".

Police Scotland's Professional Standards officials have admitted their officers began issuing the fine within a minute of Mr Kirkwood pulling in to the bus stop beside the police armed response vehicle - as shown by CCTV.

But they dismissed the complaint, saying that simply stopping in a clearway amounted to a parking offence, even if, as in Mr Kirkwood's case, he did not switch off his engine.

A complaints officers told him. "Parking on the clearway is recognised as a security risk due to its proximity to the airport.

"In regards to the current security alert status, the area is patrolled by local officers, including armed officers. stressing high security at airports meant the area was patrolled by armed and other officers."

Mr Kirkwood followed up his dismissed complaint with PIRC, but the watchdog refused to deal with him. He had accepted the fine was fair when he paid it without choosing to challenge the matter in court.

The fine was issued on May 21 when Mr Kirkwood was picking somebody up from the airport. He did not say he was a former senior officer before getting his ticket.

Outgoing Chief Constable Sir Stephen House has said he wants traffic and other officers to issue more warnings rather than fines to motorists. The force has denied that individual officers have been issued with specific personal targets. It is not unusual for armed officers to issue traffic fines for offences committed right in front of them. Senior officers have suggested it would be a dereliction of duty for them to ignore law-breaking.

Many police officers share Mr Kirkwood's perception about the decline in discretion. The Association of Scottish Police Superintendents - of which he was a member - has been warning that of a target culture since long before Police Scotland was formed.

But current officers contacted by The Herald were not sympathetic to his plight. "Mr Kirkwood is right about discretion in general but his own case is not the best example," said one. "After the Glasgow Airport attack, we really don't want cars parking on clearways near airports for obvious reasons.

"There really isn't an excuse for doing what he did and most if not all officers would have issued him - or anybody else - with a fine."

A spokeswoman for Police Scotland said: "We can confirm a 60-year-old man was issued with a fixed penalty notice on Thursday 21 May 2015 for parking in a restricted area at Prestwick Airport.

"A complaint was later received in respect of this matter and a response has been provided."