18/07/2011 17:35 BST | Updated 17/09/2011 06:12 BST

Rebekah Brooks, Rupert Murdoch, James Murdoch, Sir Paul Stephenson And John Yates All To Appear Before Parliament

Westminster is bracing itself for one of the biggest days in recent parliamentary history, as two select committees prepare to quiz some of the key players in the News of the World phone hacking and police corruption scandals.

At stake is the reputation of the police, News International and the abilities of two dozen MPs, who’ll seek answers from those at the centre of a conspiracy which has rocked both the British government and one of the world’s largest companies. Eyes across the globe will be watching the evidence.

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At midday the Home Affairs Committee will quiz two men who, until 48 hours ago, were among the most senior police officers in Britain. Sir Paul Stephenson and John Yates have both resigned from the Metropolitan Police in connection with the scandals.

John Yates resigned as an Assistant Commissioner at the Met on Monday. His main responsibilities were for counter-terrorism, but he also took charge of the first phone-hacking investigation in 2009, a probe which is now widely believed to have been flawed. He appeared before the Home Affairs Committee last week, but his evidence was judged by MPs to be "unconvincing".

Sir Paul Stephenson was the Metropolitan Police Commissioner until he resigned on Sunday night. He fell on his sword after it was alleged he’d taken hospitality from Neil Wallis, a man who had previously worked for Andy Coulson at the News of the World.

The Independent Police Complaints Commission (IPCC) is now investigating how both men handled the phone-hacking scandal.

Dick Fedorcio, the Met's director of public affairs, will also stand in the same hearing. On Tuesday he was referred to the IPCC over his relationship with Neil Wallis.

Almost immediately after their appearance, another committee will begin taking evidence. Rupert Murdoch, his son James and their sacked chief executive of News International, Rebekah Brooks, will appear before the Culture, Media and Sport Committee at 2.30pm.

Their appearance comes as a poll revealed two thirds of Britons believe James Murdoch should resign following the News of the World phone hacking scandal.

Later on this afternoon the Home Affairs select committee will hear from former Director of Public Prosecutions (DPP) Ken MacDonald, Current DPP Keir Starmer and the Solicitor representing Milly Dowler’s family, Mark Lewis.

The full line-up is:

  • 12pm: Sir Paul Stephenson (Home Affairs committee)
  • 12.45pm: Dick Fedorcio, public affairs director at the Met (Home Affairs committee)
  • 1.15pm: John Yates (Home Affairs committee)
  • 2.30pm: Rupert Murdoch and James Murdoch (Culture, Media and Sport Committee)
  • 3.30pm: Rebekah Brooks (Culture, Media and Sport Committee)
  • 5.30pm: Lord Macdonald, former director of public prosecutions (Home Affairs committee)
  • 6pm: Keir Starmer, director of public prosecutions (Home Affairs committee)
  • 6.20pm: Mark Lewis, lawyer for the Dowler family (Home Affairs committee)

It’s a big day not just for the MPs sitting on these two committees. It’s the biggest test of the ability of backbench MPs to hold outsiders to account since the committee system was reformed last year. No longer chaired by party stooges and filled with MPs who could be expected to toe the line, the new committee model was created with the express aim of strengthening Parliament.

Much will depend on the performance of the two committee chairmen, Labour’s Keith Vaz and the Tory John Whittingdale. Vaz was widely praised for his handling of John Yates’ evidence last week. He was congratulated by MPs from all parties after their meeting last Tuesday when the police chief was grilled.

But perhaps the greatest pressure falls on John Whittingdale. Facing up to one of the most powerful media barons in the world would be no small order under any circumstances, but Whittingdale has two further challenges; firstly Rebekah Brooks remains on police bail, and those conditions may place limits on what she’s prepared to say.

Whittingdale will also have to prove himself genuinely independent of the Conservative Party. There will be pressure upon him and other committee members to conduct a forensic and detailed examination of the activities of Andy Coulson during his time at the News of the World. The answers could further destabilise the position of David Cameron, who is planning to fly back to Britain tonight, cutting short his tour of Africa to respond to the latest political crisis in London.

The evidence given today could have profound implications, not just for the Murdochs and the Metropolitan Police, but also for how damaged the prime minister will be as a result of his links to Brooks and Coulson.