The Electoral Commission should face a "full investigation" over its decision to allow an extremist party to use a slogan featuring murdered soldier Lee Rigby, the Government said.
The watchdog issued an apology yesterday for allowing Britain First to use the description "Remember Lee Rigby" on voting slips for next month's European elections.
The poll on May 22 takes place on the first anniversary of Fusilier Rigby's death. The 25-year-old father of one was killed near Woolwich Barracks in south-east London.
Cabinet Office Minister Greg Clark has now written to House of Commons speaker John Bercow to request an investigation into the error is brought forward by the parliamentary committee which oversees the commission's work.
Clark added he wants the Speaker's Committee, which is chaired by Bercow and includes Deputy Prime Minister Nick Clegg among its cross-party members, to ensure steps are taken to prevent "such a mistake ever happening again".
The commission said it had signed off the slogan for the party to use across the UK.
But Britain First has opted not to deploy it in Scotland, and is not believed to be fielding candidates in England.
It is not clear if any individuals are facing disciplinary action over the error.
Clark said: "It is sickening that anyone should attempt to make political capital out of Lee Rigby's murder.
"The whole country will be outraged that the memory of Lee Rigby should be abused in this way, and our heart goes out to his family, friends and colleagues.
"Parliament has put the powers on the registration of political parties and the descriptions they use in the hands of the Electoral Commission.
"I have spoken to the chair of the commission, and the commission has acknowledged that it was a grave error to allow this wording to appear.
"I have written to the speaker of the House of Commons, in his capacity as chairman of the Speaker's Committee overseeing the commission, to ask the committee to ensure there is a full investigation and ensure steps are taken to prevent such a mistake ever happening again."
Commission chair Jenny Watson said yesterday Britain First's party description "Remember Lee Rigby" should "never had been permitted".
Ms Watson added she had apologised to Fusilier Rigby's family.
She went on: "We are sorry that the decision we made means that voters in Wales will now see the description on the ballot paper when they vote.
"We have looked carefully at what can be done to stop this from happening and we greatly regret that we have not found a way for the ballot papers to be changed. We will ensure the description is removed from the register for future elections."
Bercow would like an independent inquiry to be conducted as a "matter of urgency", according to his spokeswoman.
She said: "The speaker was told about the Electoral Commission's decision this afternoon. He understands the grave concern felt over this alarming development and awaits (Clark's) letter.
"The speaker wishes to see an independent inquiry, conducted as a matter of urgency.
"He will look forward to the publication of the report of that inquiry, which he and his colleagues will carefully consider."
It is thought there would have to be a consensus among the committee for an investigation to take place.Suggest a correction