Derek Conway, the disgraced former Conservative MP, will escape a police investigation into his conduct after the Crown Prosecution Service ruled that gaping holes in the records of MPs' expenses would make bringing charges impossible.
In a move that will intensify the pressure on MPs to tighten their system of expenses and office allowances, Scotland Yard announced last night it would not be "appropriate" to launch an investigation into Conway after being advised by the CPS that "the lack of systems in this case to account for MPs' expenses would severely undermine the viability of any criminal investigation leading to a prosecution".
The Metropolitan police statement added: "In these circumstances we do not believe that it is appropriate for a police investigation to be instigated."
The gaps in the parliamentary scrutiny drew immediate criticism and calls for wholesale reform. Martin Bell, the former BBC journalist who was elected to parliament on an anti-sleaze ticket in 1997, told the Guardian: "This shows the need for external regulation. This has happened again and again and again.
"Anyone who has tried to make MPs more accountable - from Elizabeth Filkin to Alistair Graham [both former Commons sleaze watchdogs] - has been removed. We are in a state of constitutional crisis. MPs are supposed to set an example to the rest of us and yet they think there is one rule for them and another for the rest of us."