FIVE years ago, I took a phonecall at work which started a chain of events I could never have anticipated.

That April morning in 2012, The Northern Echo reported on the outcome of the case of retired police officer Sultan Alam, who had been awarded an £800,000 compensation package after being "stitched up" by fellow officers at Cleveland Police and wrongfully jailed.

After the case, the force's assistant chief constable Sean White told media "lessons had been learned".

He also said: "Whilst we respect Mr Alam's views, we do not believe that the force is a racist organisation and we are working hard to ensure that everyone in the force upholds those views. There is no ongoing investigation or surveillance and the matter is concluded."

That statement led one officer – despite the threat of dismissal for leaking information to the media – to pick up the phone to The Northern Echo.

That phonecall must have lasted no more than 40 seconds. Anonymously, he told me that an ongoing internal report commissioned by the Chief Constable had concluded that there were "elements of institutional racism" within Cleveland Police.

Effectively, he said, the force had lied. The internal Equality Report was a damning document, full of ethnic minority officers' claims of victimisation and discrimination by colleagues, leading the Chief Constable of the time, Jacqui Cheer, to address the officers personally just days before the Alam case. The officer's phonecall led to a front-page story the next day.

I later found out that officer was Mark Dias, who within just days had admitted to the force that he was the whistleblower. However, my colleague Graeme Hetherington had other sources within the force who had passed on other information – and Cleveland Police was desperate to track down the source of all the leaks.

Over a period of several months, its professional standards department illegally obtained data from our personal phones, and from police officers it suspected of leaking us information.

However, none of the information leaked was procedural, or could affect police investigations.

It was just material that would embarrass the force. Essentially, Cleveland Police seriously compromised people's privacy, human rights, and solicitors' and journalists' privilege to report on the public interest, to spare its own blushes.

That one phonecall set in motion a series of events which has involved high court judges, a specialist and secretive court, the Inspectorate of Constabulary, the police watchdog the IPCC, and the world's media.

The case has been featured on national television and in newspapers across the world, in the New York Times and the Washington Post.

Even now, under the scrutiny of all these bodies, and the media, Cleveland Police has persisted in not disclosing all the information it was supposed to, leading to criticism from the judges yesterday.

If the force, as it says, really wants to learn lessons, here's one: Be open. Stop hiding things. Disclose all, and start anew.

That is the only lesson that has been clear along the way, and yet it hasn't quite been learned yet.