Peers have hit out at the "outrageous" tax deal struck with Google as ministers came under increased cross party pressure over the £130 million agreement.

At question time in the Lords, Treasury spokesman Lord Ashton of Hyde admitted it was a "tricky question" to determine between statements by the Prime Minister, Chancellor and others on the deal.

But he insisted: "We want fair payment of tax by everyone - be they large small companies or individuals."

The Google tax deal has prompted calls from senior MPs for greater transparency as the amount to be paid by Google has been branded "derisory".

HM Revenue and Customs has insisted that Google will pay "the full tax due in law" as a result of the deal.

Lord Ashton said the Government was tackling avoidance and "aggressive tax planning" as well as evasion and non-compliance with the aim of recovering billions of pounds over the next five years.

But Labour's Lord Dubs said: "It sounds good but on examination it isn't. Can you explain the Government's attitude to the Google deal? The Chancellor says it's a great success. The Prime Minister doesn't seem to know and says it's a good step forward and many Conservatives say the deal is derisory.

"It's difficult to know what the Government's view is and could you say something about letting the truth come out about deals like this. In the (London) Evening Standard today there is an opinion poll saying 80% of the public want more openness.

"Surely it's time we said goodbye to taxpayer confidentiality so we could learn what is going on in our name and have a better tax system."

To laughter, Lord Ashton replied: "It's a tricky question to determine between the different statements of the Prime Minister, the Chancellor and others.

"I'm afraid I haven't seen all their comments in context and I would need to see those before I'm able to deliver my final judgment."

He said taxpayer confidentiality was a long established principle, which should be maintained.

Tory former Cabinet minister Lord Crickhowell said many small businesses who found themselves paying more corporation tax than the big international corporations felt government action was "quite inadequate".

He called for ministers to make a "really determined effort to sort out this unacceptable situation".

Lord Ashton told him: "We expect all companies large and small to be treated equally and pay the tax that is due.

"This Government has reduced corporation tax and the quid pro quo for that is that when it is due on taxable profits it should be paid."

Lord Ashton said the Government was also leading efforts to tackle the issue internationally.

For Labour, Lord Davies of Oldham accused the Government of using the same "trick" in the Lords as had been used in the Commons where "junior ministers responded" to questions instead of those making the decisions.

"You've admitted to the House you haven't got a clear line to answer the question posed to you," he told Lord Ashton.

"But the rest of the country is quite clear that the deal struck with Google is an outrageous one.

"How is it that the US ... can tax major companies with considerable success, whereas in the UK we find multinational companies in particular paying absolutely derisory rates of corporation tax?"

Lord Ashton said HMRC had "taxed the full amount of UK taxable profits at the statutory corporation rate".

Plaid Cymru's Lord Wigley warned of the depth of anger among small businesses who paid their tax on time and then saw "fat cats getting away with it in this manner". He suggested a turnover tax to tackle the problem.

Lord Ashton said turnover had never been taxed but ministers were making sure that "taxable profit rests in the country where the economic activity takes place".

For the Liberal Democrats, Baroness Kramer said 55% of calls by taxpayers and small businesses were not answered by HMRC and suggested the Government spent the "derisory" Google settlement on more phone staff.

Lord Ashton said HMRC had recruited 3,000 new staff into customer service to address the problem.