Three Labour MPs and a Conservative peer told a judge today they will use a 320-year-old law to argue they should not be prosecuted over the expenses scandal.
MPs David Chaytor, Elliot Morley and Jim Devine, along with Lord Hanningfield, will insist their case should not be tried by a jury and instead dealt with by House of Commons authorities.
In an unprecedented hearing at City of Westminster Magistrates' Court, all four Parliamentarians said they would plead not guilty to fiddling claims for allowances.
The MPs asked to be excused from standing in the secure glass dock at the back of the court - but their request was refused.
District Judge Timothy Workman agreed the case was so serious it should be heard at a higher court and released the four defendants on unconditional bail to appear at Southwark Crown Court on March 30.
If convicted, they face a maximum sentence of seven years in prison.
Barrister Julian Knowles, for the MPs, told the court they would argue they were protected by parliamentary privilege, covered in the 1689 Bill of Rights.
"My clients should not be understood as saying that they are above the law - that would be quite wrong," he said.
"Parliamentary privilege is part of the law - and it is for Parliament to apply the law in their cases."
He said the case was of "high constitutional importance" but added the criminal courts had "no jurisdiction" over them.
"Proceedings in Parliament cannot be impeached or questioned in any court or place outside Parliament," he said.
Addressing a court packed with journalists and members of the public, he stressed the men denied any wrong-doing.
"They unequivocally and steadfastly maintain their innocence," he said.
In a separate hearing immediately after the MPs', the court was told Hanningfield would also argue he was covered by Parliamentary privilege.
His lawyer Rupert Bowers said he would deny charges of wrongly claiming for "repayment of travelling and other expenses".
The three MPs and peer left court without commenting where they were mobbed by the media and a handful of protesters chanting "give us our money back", "pigs" and "oink, oink".
In a statement, Hanningfield said he was "devastated" at the proceedings.
His spokesman Mark Spragg said: "He is devastated to be in this position. He feels he has been singled out. He does not believe he has done anything dishonest."
Bury North MP Chaytor, 60, of Todmorden, Lancashire, is accused of falsely claiming rent on a London flat he owned, falsely filing invoices for IT work and renting a property from his mother, against regulations.
Scunthorpe MP Morley, 57, of Winterton, North Lincolnshire, allegedly falsely claimed £30,428 in interest payments between 2004 and 2007 towards a mortgage on his home he had already paid off.
Livingston MP Devine, 56, of Bathgate, West Lothian, is said to have wrongly submitted two invoices worth a total of £5,505 for services provided by Armstrong Printing Limited.
He also faces a second charge alleging he dishonestly claimed cleaning and maintenance costs of £3,240 by submitting false invoices from Tom O'Donnell Hygiene and Cleaning Services.
Hanningfield, also known as Paul White, 69, of West Hanningfield, near Chelmsford, Essex, faced six charges of making dishonest claims for travelling allowances.
Each charge claimed the former leader of Essex County Council "purported to show that you were entitled to be paid expenses when the conditions entitling you to payment of such expenses had not been fulfilled".