A controversial backbench Bill to enshrine in law a referendum on Britain's membership of the European Union was branded a "disgrace" in the Lords today.
Labour's Lord Foulkes told peers the European Union (Referendum Bill) was "not fit for purpose".
He said: "It's been hastily got together and it shows. It is a Government Bill trying to patch over divisions in the Tory party and try to outflank Ukip."
Lord Foulkes' attack came as peers began detailed line by line committee stage debate on the Bill, which has already completed its Commons stages.
He is one of a number of critics of the Bill who have tabled more than 70 amendments to it.
With time running out before the next session of Parliament, peers are under pressure not to delay the legislation and stop it becoming law.
The Bill provides for a referendum to be held before the end of 2017 in line with Tory party plans.
Tory Lord Cormack said the Commons had neither "the stamina to talk the Bill out or the courage to go into the lobbies in any numbers....".
He added: "We are being used."
Lord Foulkes said the legislation was a "Tory party Bill masquerading as a private member's Bill".
He added: "It's also a disgrace that we are discussing it because the coalition government chief whip (Baroness Anelay of St Johns) has used her position improperly to put it ahead of all other private member's Bill."
But in angry exchanges, Lady Anelay denied this charge, insisting she had followed "precisely the same procedures" as her predecessors and "absolutely followed every rule".
As debate got under way on the Bill in a crowded chamber, former cabinet secretary and independent crossbencher Lord Armstrong of Ilminster said the question proposed for the referendum was "inappropriate, confusing and potentially misleading".
The Bill states that voters should be asked: "Do you think that the UK should be a member of the EU?"
But Lord Armstrong said that might be appropriate if the UK was not already a member of the EU and were applying for membership.
He said the question should be "clear and unambiguous" as well as being in line with that recommended by the Electoral Commission.
Lord Armstrong said the question should be: "Should the UK remain a member of the EU or leave the EU?"
In a damning assessment of Labour peers, Conservative former Cabinet minister Lord Forsyth of Drumlean said he would not stand in the way of giving the British people their say on Europe.
Urging the Lords not to vote in favour of the amendments, he said: "If the Bill is amended, it is going to go back to the House of Commons, where it's going to run out of time.
"So let us be clear about what is going on here. And all this kind of self-righteous talk about how we have a duty to consider this Bill properly, the consequence will be that the British people are not guaranteed a say before 2017 on whether they wish to be members of the European Union."
He added: "We fought that battle on the basis that the other place was supreme, that the will of the other House should always be carried forth. And they clearly expressed the will of the other House was that this Bill should reach the statute book, otherwise it would not have come here and this House has to recognise this.
"Now it may be that this Bill came to this House because the parties opposite did not have the courage to do it there, but the fact is that it has been passed by the House of Commons."
Lord Forsyth warned that failure to pass the Bill would not only have implications for the British people, but also the House of Lords itself.
"Even worse than frustrating the will of the House of Commons," said Lord Forsyth, opposition peers are "denying the British people the opportunity to be sure at the next election that, whatever happens, there will be on the statute book provision for those people to have their say on the most important question facing our country's future."
He suggested that the opposite result would reinforce the argument in favour of reforming the House of Lords.
"And I think that will have very damaging consequences for this House, because people will say 'What on Earth are these unelected people doing from preventing us from having our say?'," said Lord Forsyth.