Labour leader Ed Miliband said he was “shocked” by evidence that Google was avoiding tax just days before he is due to attend a high-profile event organised by the internet giant.
Mr Miliband said there was a “culture of corporate irresponsibility” among some firms.
A senior Labour source said Mr Miliband would be taking his message “loud and clear” to Google when he appears at a conference next week.
Google today denied trying to “disguise” the way its business operated to minimise its tax bill in the UK.
Appearing before the Commons Public Accounts Committee, Google vice-president Matt Brittin insisted he stood by evidence he gave last year that all the firm’s advertising in Europe was sold through its offices in Ireland.
But in a series of testy exchanges, committee chairman Margaret Hodge said his claims were contradicted by documentation MPs had seen and evidence from a “stream” of whistleblowers.
“It was quite clear from all that documentation that the entire trading process and sales process took place in the UK,” she told him.
“I simply suggest to you again that you think about what you actually said on November 12 which was that ‘anyone who buys advertising from us in Europe buys from Google in Ireland, from our expert teams’. That is not what the whistleblower told us and that is not what the documentation demonstrated.
“I think you should think really carefully about what you said to us and whether or not that holds true.”
Mr Brittin said the evidence related to the period before he joined the company six and half years ago and that suggestions that Google was trying to “disguise” the way it operated were “just not true”.
“I stand by what I said. I described very clearly how we operate,” he said.
Mr Miliband said: “People will be shocked by the evidence that Google is going to extraordinary lengths to avoid paying their fare share of tax.
“It comes on top of other firms apparently engaging in similar practices. It is evidence of a culture of corporate irresponsibility among certain firms which is totally unacceptable.
“And of course we’ve now seen allegations about petrol fixing as well.
“It comes at a time when ordinary families are seeing services cut, their taxes rising and so many businesses are struggling to make ends meet and are actually doing the right thing and paying their fair share of taxes.
“As so often under this Government, I think it is evidence of one rule for those at the top and another rule for everyone else.
“David Cameron says we have to just wait for international action. He’s wrong.”
Mr Miliband will appear at Google’s Big Tent UK event in Hertfordshire next Wednesday, where other speakers include the firm’s executive chairman Eric Schmidt.
A senior Labour source said: “We will take Ed’s message loud and clear to Google.”