Channel 4 has been cleared of misconduct by the broadcasting regulator over its cash-for-access sting on two former foreign secretaries.
Ofcom said the Dispatches programme on Sir Malcolm Rifkind and Jack Straw had not breached the broadcasting code, insisting the channel represented the former MPs' views in a fair manner.
The regulator found that the documentary did not treat the politicians unjustly or unfairly, had given them an appropriate and timely opportunity to respond to the allegations, and that the secret filming was warranted in the circumstances.
The ruling follows criticism of Channel 4 by the Parliamentary Commissioner for Standards, which cleared Sir Malcolm and Mr Straw of wrongdoing and called into question the accuracy of the reporting.
In the sting, the MPs were secretly filmed by undercover reporters claiming to represent a Hong Kong-based communications agency called PMR that was seeking to hire senior British politicians to its advisory board.
Sir Malcolm was said to have claimed he could arrange ''useful access'' to every British ambassador in the world because of his status, while Mr Straw boasted of operating ''under the radar'' to use his influence to change European Union rules on behalf of a commodity firm which paid him £60,000 a year.
Following Parliamentary Standards Commissioner Kathryn Hudson's criticism of the reporting, which also featured in the Telegraph, Channel 4 issued a defiant statement defending its journalism and took the unprecedented step of asking Ofcom to look at the case.
Ofcom has now cleared Channel 4 of any breach of the rules.
In its latest bulletin, the watchdog said: "In Ofcom's view, the programme was a serious piece of broadcast journalism and that there was a significant public interest in the programme makers secretly filming both Sir Malcolm Rifkind and Mr Straw.
"We also considered that there was a genuine public interest justification for Channel 4 using some of the secretly filmed footage in the programme as broadcast in order to bring to the attention of the wider public the conduct of the two prominent parliamentarians who had held a number of senior ministerial positions, in relation to their commercial interests and their attitude to the potential conflict these interests might have with their political commitments.
"Ofcom recognised that the allegations made in the programme about Sir Malcolm Rifkind and Mr Straw were serious in nature and that the broadcast of extracts from the secretly filmed footage of their meetings with the undercover reporters had the potential to impact adversely on the MPs' reputations.
"However, notwithstanding this, Ofcom considered that the public interest in broadcasting the secretly filmed footage in the programme overrode the potential negative impact the broadcast would have on the MPs.
"In coming to that view, we had regard to Channel 4's and the programme maker's rights to freedom of expression, as well as the public's right to receive information and ideas, together with the public interest, and we considered that these, in all the circumstances, outweighed the rights of the two MPs featured."
Channel 4 Dispatches editor Daniel Pearl said: "We are delighted this important piece of public service journalism has been thoroughly vindicated by the independent regulator.
"This was a rigorously detailed investigation which paid scrupulous attention to fairness and accuracy at all times.
"We are pleased that Ofcom has recognised that the secretly-filmed comments, 'accurately represented the discussions that took place between the MPs and the undercover reporters'."