20/11/1996 Ray Mallon becomes the new head of Middlesbrough CID and takes the extraordinary step of pledging to quit if he fails to slash the crime rate by 20 per cent.

08/01/1997 His confrontational style of policing, known as Zero Tolerance, wins the backing of Labour leader Tony Blair.

31/03/1997 No better example of his tough style is shown when he spots two men trying to steal his car, chases them across fields and arrests them.

06/08/1997 Nine months into the job and his pledge to cut crime appears to be working as figures plummet towards the key 20 per cent mark.

27/10/1997 The first hint of trouble in the force emerges when a court case collapses because evidence has come from a suspended officer.

01/12/1997 Det Supt Mallon is suspended by the force's disciplinary officer, Assistant Chief Constable Robert Turnbull. He pledges to clear his name after allegations that he had leaked information about a police corruption investigation - codenamed Operation Lancet - and to have engaged in alleged activities which could be construed as criminal conduct.

06/12/1997 Supporters launch a petition demanding Det Supt Mallon's reinstatement.

08/12/1997 Det Supt Mallon clears his desk.

10/12/1997 He is replaced by Superintendent Adrian Roberts.

12/12/1997 Det Sgt John McPherson, 51, Det Supt Mallon's right-hand man, is transferred to uniform.

03/02/1998 A 30,000-name petition demanding the reinstatement of Det Supt Mallon is handed to the Home Office.

05/02/1998 A detective is arrested over theft allegations following an internal investigation into alleged thefts from Middlesbrough police station's stolen property store. The same day, another detective is suspended without pay after quitting his job for a new life in Australia, without telling his bosses.

07/02/1998 Police question journalists working for The Northern Echo as part of their investigation into internal corruption claims.

23/02/1998 Home Secretary Jack Straw pledges his continuing support for Zero Tolerance but he says he cannot intervene on Det Supt Mallon's behalf.

12/03/1998 Cleveland Police launches a new inquiry into Det Supt Mallon over his expenses and movements since his suspension on December 1.

25/03/1998 Cleveland police is rocked when a man wins £1,400 after being assaulted by officers.

03/04/1998 Det Sgt John McPherson is exonerated after an investigation into allegations against him of improper conduct.

16/04/1998 A vote of no-confidence is passed in Cleveland's Chief Constable Barry Shaw over his handling of the Mallon saga at a packed public meeting in Middlesbrough.

25/09/1998 Files about the Teesside police officers being investigated in the anti-corruption inquiry are passed to criminal lawyers.

24/11/1998 The investigation takes a dramatic twist when Det Supt Mallon is cleared of fiddling his expenses.

01/12/1998 Police reveal the full list of accusations facing Det Supt Mallon after questioning him for the first time. Allegations include: conspiracy to pervert the course of justice and related matters; suppressing evidence; failing to conduct appropriate inquiries; disobeying the orders of senior police officers; acting in an oppressive manner to junior officers.

10/12/1998 Jack Straw again refuses to intervene.

26/01/1999 The man who suspended Det Supt Ray Mallon announces his retirement. Assistant Chief Constable of Cleveland, Robert Turnbull has served just 19 months of a five-year contract with the Cleveland force.

19/02/1999 Two detectives are charged with stealing from a police station. One, 39-year-old Det Insp Russ Daglish, is suspended. The other is Brendan Whitehead.

15/04/1999 It is revealed that Robert Turnbull is to become deputy commissioner of the Royal Turks and Caicos Islands police.

16/04/1999 Hundreds of thousands of pounds of taxpayers' money is wasted after senior officers at Cleveland Police libel three of their uniformed men.

20/04/1999 Det Supt Mallon is cleared of wrongdoing in his relationship with the media.

09/07/1999 Calls are made for the police corruption inquiry to be wound up after it is revealed that some of the investigating officers are under investigation themselves. Officers from two outside forces are brought in to look into the alleged activities of a small number of Teesside detectives on the Operation Lancet team. Ashok Kumar, MP for South Middlesbrough and East Cleveland, says the situation is turning into farce with public credibility in Cleveland Police now seriously at risk.

14/09/1999 Allegations are made against the man heading the Lancet investigation. Andrew Timpson, Chief Constable of Warwickshire, goes on sick leave. However, the investigation into Mr Timpson is said to be unconnected with Operation Lancet. Mr Timpson is replaced on the Lancet inquiry by Lloyd Clarke, Deputy Chief Constable of West Yorkshire.

04/11/1999 Richard Brunstrom, assistant Chief Constable with Cleveland Police, quits and moves to North Wales Police.

01/12/1999 Det Supt Mallon marks the second anniversary of his suspension with a scathing attack on the Police Complaints Authority which, he claims, smeared him. He predicts the investigation will end without criminal charges being laid against him, and he calls on Home Secretary Jack Straw to instigate a public inquiry so that the main players can be called to account.

10/02/2000 Det Supt Mallon acknowledges that he may never be allowed to return to policing even if he is cleared of any criminal wrongdoing. Andrew Timpson retires.

06/03/2000 Cleveland's acting Deputy Chief Constable David Earnshaw retires while he is the subject of a Police Complaints Authority investigation.

14/03/2000 A decision on whether the first police officers were to be prosecuted as part of Operation Lancet was to be announced later this month. But Solicitor General Ross Cranston warned that further files relating to the inquiry have yet to be considered.

01/04/2000 It is announced that there are no gounds for disciplinary action against Cleveland's Acting Deputy Chief Constable David Earnshaw .

13/06/2000 Public inquiry demanded into Operation Lancet by MP Ashok Kumar amid fears the cost of the probe have run to nearly £5m.

15/06/2000 MP Dari Taylor, member for Stockton South, claims Cleveland Police is losing public support.

20/06/2000 Crown Prosecution Service announces there will be no prosecution of Det Supt Mallon as there is insufficient evidence.

23/06/2000 Det Supt Mallon challenges his bosses to reinstate him.

24/06/2000 Chief Constable Barry Shaw faces calls to quit after a judge says a "catalogue of errors" turned an inquiry into the alleged police theft of a £20 boiler into a £500,000 farce. Judges Henriques was so angered by the collapse of the case against Det Insp Russ Daglish and Det Con Brendon Whitehead that he ordered Chief Supt Kevin Pitt to appear before him.

18/07/2000 Chief Supt Kevin Pitt becomes the fifth senior Lancet officer not to see the corruption inquiry through.

08/08/2000 Det Supt Mallon makes a formal complaint to the Home Secretary that senior officers have conspired to pervert the course of justice. He asks solicitors to write to Jack Straw alleging the conspiracy against him. Members of Det Supt Mallon's legal team say they have compiled evidence to back the claims.

12/09/2000 Cleveland Police are accused of "scraping the barrel" to find 14 disciplinary charges against Det Supt Mallon. The Police Complaints Authority reveals it will charge Det Supt Mallon with 14 unspecified offences later in the week.

06/12/2000 The Crown Prosecution Service says "there is insufficient evidence" to bring a prosecution against ex-assistant Chief Constable Richard Brunstrom.

22/12/2000 The CPS reveals there will be no criminal charges arising from Operation Dollar, an investigation into Cleveland Police by West Yorkshire Police, into allegations made by Det Supt Mallon.

13/02/2001 Barry Shaw hints that the inquiry will end with all 393 criminal allegations being thrown out.

22/02/2001 Official confirmation is given that Operation Lancet is over and no charges are to be brought.