Sir Christopher Kelly was 'shocked' by the revelations of MPs' expenses
The man heading up an independent inquiry into MPs' expenses has told the BBC he was "shocked" by some of the revelations in the Daily Telegraph.
Sir Christopher Kelly said he had been concerned about the system "for some time" and had asked to do an inquiry before Gordon Brown requested it.
The Telegraph printed scores of stories based on leaked receipts from claims.
Meanwhile, Commons leader Harriet Harman has said details of MPs' second jobs will be published on 1 July.
Sir Christopher, whose committee on standards in public life's inquiry into MPs' allowances begins public evidence sessions next week, reiterated that he did not expect to report back until the autumn.
Last Wednesday the senior Labour MP Sir Stuart Bell said the recommendations were expected "during June" and the prime minister had asked the committee to report back in July.
But Sir Christopher told BBC One's Andrew Marr Show that while he was conscious of the need to report quickly to "get this dreadful episode behind us", he could not be exact.
"We are now trying to produce our report by the autumn, a key date is clearly soon after Parliament comes back form their summer recess, in October."
Until we had the revelations from the Daily Telegraph I don't think the committee had any idea of the depth of what was happening
Sir Christopher Kelly
He said the committee had been "concerned" about the system of MPs' expenses and had had its "eye on it" for some time: "The truth is that actually we proposed doing the study to Gordon Brown before he proposed it back to us."
"But until we had the revelations from the Daily Telegraph I don't think the committee had any idea of the depth of what was happening."
He added: "I was both surprised and I think it is fair to say, shocked."
The Commons authorities had long fought attempts to release detailed breakdowns of MPs' claims under their controversial second homes allowance - but had been forced to compile receipts after losing a High Court battle under the Freedom of Information Act.
But before they could be published widely, the Daily Telegraph got hold of copies of millions of receipts and began publishing stories about claims by MPs from all parties.
The fallout and public anger has led to money being paid back, MPs announcing they will step down and has been blamed in part for Labour's disastrous showing at the European and English council elections last week.
It has been a traumatic thing, this big collapse in confidence and the crisis over MPs' expenses
Harriet Harman Commons leader
Commons leader Ms Harman said MPs had already agreed to give "absolute transparency" on expenses and audit all claims made over four years, paying back money where appropriate.
From 1 July people would also know how much time and how much money MPs get from second jobs.
The plan has been seen as an attempt to embarrass the Conservatives - it means all MPs have to register more details of their outside earnings.
She said she hoped a new independent Parliamentary standards authority to run MPs' expenses would be law before MPs leave for the summer recess.
"I think that will not only be important for the public but also a relief to MPs because we don't want to be doing it ourselves," she said.
"It has been a traumatic thing, this big collapse in confidence and the crisis over MPs' expenses.
"But what we are going to end up with a much cleaner, better clearer system."
Interim changes to the expenses system have been brought in while MPs await the findings of Sir Christopher's committee.
He said they were "in the right direction" but his committee would not hesitate to go further if necessary.
He said if "complete transparency" could be guaranteed and a proper system of audit - rather than the "pretty poor" controls of the past - it would make a great deal of difference.
But he pointed out while his committee could make recommendations - it was ultimately for Parliament to decide whether to follow them or not and for the media to scrutinise them.
Without a written constitution, they could be scrapped in the future, he added.
"There may well be ways however to make it more difficult to do that through primary legislation," he said.
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