A Commons committee has criticised government plans by to restrict access under freedom of information laws.
The constitutional affairs committee, which also attacked a private members' bill attempting to exempt MPs from the 2000 Freedom of Information Act, said ministers had failed to produce evidence that changes were necessary.
Under the Act government departments have to answer requests that cost less than £600 to process.
But constitutional affairs secretary Lord Falconer has proposed including within the £600 limit the cost of the time taken by ministers and officials to read and consider each request, meaning many more applications would be turned down.
Critics of the changes point out this would disproportionately affect requests for information relating to high-profile or controversial issues.
The cabinet minister also wants to treat multiple requests from the same company, organisation or individual made in a three-month period - even if they are on different subjects - as one request. This could then be turned down if it breached the £600 limit.
A report by the committee published on Monday said the proposals were "unnecessary, unpopular and undesirable".
"We conclude that the proposed regime could result in public authorities avoiding answers to embarrassing, contentious or high-profile cases," the report said.
"No clear evidence to support the decision that a change to the charging regime was necessary has been published."
The report also criticised the Freedom of Information (Amendment) Bill, a private members' bill launched by former Tory chief whip David Maclean and given tacit support by the government, which would mean MPs being made exempt from disclosure rules in order to protect constituency correspondence.
Committee chairman Alan Beith said: "The FoI Act works. It enhances the rights of the public.
"Neither the government nor MPs should be seeking to limit its effectiveness, and there is no evidence here to support either the government's proposals on fees or the Bill. I am hopeful that both will now be dropped."
Commenting on the report, Liberal Democrat justice spokesman Simon Hughes said: "This report makes clear that David Maclean's attempt to change the rules and exclude Parliament from freedom of information requests was quite wrong, badly thought through and completely unjustified.
"The committee makes clear that there is no compelling case to change the present position.
"It also confirms that major decisions on the rights of the citizen should not be taken without full facts and a persuasive conclusion.
"Thank goodness the Lords saved the House of Commons from a bad law and public embarrassment."
The Lib Dems made several attempts at filibustering to block Maclean's Bill, which now seems to have been shelved in the absence of a peer willing to steer it through the Lords.
