Theresa May must apologise over Gove row - Labour
Home Secretary Theresa May is facing Labour calls for a public apology over her part in a row with Education Secretary Michael Gove.
Mr Gove has apologised to the prime minister over the briefing war with the home secretary's department.
The two sides clashed over how to deal with claims of a hardline Muslim plot to take over some Birmingham schools.
Mrs May's special adviser has been forced to quit - but Labour says that is not enough.
The row between two of the cabinet's biggest hitters overshadowed this week's Queen's Speech - sparking a furious reaction from David Cameron, who ordered an internal investigation to find out who was to blame.
Mrs May's special adviser Fiona Cunningham was found to have been the source of a negative briefing against Mr Gove and has stood down.
Mr Gove has also apologised to Home Office counter-terror chief Charles Farr after comments critical of him appeared in the Times, attributed to a Department for Education source.
Foreign Secretary William Hague told the BBC's Andrew Marr show that no further action over the row was needed.
"There has been a disciplinary matter within the government which the prime minister has dealt with in a very firm, clear way."
He said the investigation into the affair by the Cabinet Secretary Sir Jeremy Haywood was "the right thing to do", and that the prime minister was "making sure there is team discipline" within the government.
The government was fully focused on "tackling extremism in schools", he added.
But Labour's Yvette Cooper said the home secretary still had questions to answer - and may have breached the Ministerial Code over the release of a private letter she had written to Mr Gove criticising his department.
'Drain the swamp'
Ms Cooper told Andrew Marr: "In this row we've seen the education secretary apologise, the special adviser to the home secretary resign, but we've so far heard nothing from the home secretary even though it looks pretty clear that she has breached the Ministerial Code by writing and then authorising the publication of this letter.
"Well, the prime minister is responsible for enforcing the Ministerial Code, he needs to act and to make sure that that happens, at the same time as making sure they address these more important issues about what's happening in schools and communities."
By Iain Watson, political correspondent
On Monday, Michael Gove faces MPs just 48 hours after having to make humiliating apologies both to the prime minister and a Home Office official.
But Labour are keen to ensure Theresa May also remains in the firing line.
With Downing Street indicating it's unlikely to take any further action against Mrs May, they think they can damage the prime minister by suggesting he is not implementing the very Ministerial Code to which he wrote the foreword in 2010 - promising to rebuild confidence in the political system.
Labour also believe they can dent the prospects of a possible future leader of the Conservatives, as Theresa May has ambitions in that direction.
But this spat is not all bad news for the prime minister. Mr Gove had been known to favour George Osborne as an eventual successor to David Cameron.
Mrs May intended to stand in his way. But now with both ministers somewhat chastened, speculation about the succession is likely to be suppressed - and Conservative cabinet colleagues will be more aware of the dangers of failing to maintain a united front in public this side of the election.
The briefing war began when a source close to Mr Gove spoke to the Times over the alleged Birmingham schools plot, accusing the Home Office of failing to "drain the swamp" of extremism.
The "anonymous source" also criticised Mrs May's counter-terrorism adviser, Charles Farr.
In a response on its website, the Home Office released the letter Mrs May had written to Mr Gove, accusing his department of failing to act when concerns about the Birmingham schools were brought to its attention in 2010. It has now been removed from the site.
Ms Cooper has written to the prime minister, along with shadow education secretary Tristram Hunt, calling for an apology from Mrs May - and for the full facts about the row to be published to restore public confidence.
The letter says: "What action have you taken in response to a breach of the Ministerial Code by one of your most senior cabinet ministers?
"Will the home secretary also be apologising or are some ministers exempt from enforcement of the Ministerial Code?
"The best way of ensuring people know the facts is to publish the cabinet secretary's investigation."
The shadow ministers add: "We need assurance that the government is addressing the concerns raised around the schools in Birmingham and that the lack of oversight and accountability under the new system for academies will be addressed as a matter of urgency."
Labour is also demanding to know about any financial settlement received by Fiona Cunningham.
"If she has been awarded severance pay this would amount to £37,000, which is the maximum possible and £10,000 above the UK national average wage. This would be considered unacceptable in light of the circumstances of her departure," said shadow cabinet office minister Jonathan Ashworth.
The row centred on the alleged plot to infiltrate Birmingham schools, but Westminster insiders say it was fuelled by the battle for who will succeed David Cameron as Conservative leader when he steps down.
Mr Gove will be quizzed by MPs over the alleged "Trojan Horse" plot on Monday. Reports by education watchdog Ofsted into 21 schools in Birmingham at the centre of the allegations are also due to be published on Monday.
According to the Guardian, Ofsted is to rate one, Park View academy, as inadequate.
Five of the schools are expected to be put into special measures, according to BBC Newsnight policy editor Chris Cook.
The "Trojan Horse" claims were detailed in a letter which was made public in March. It has not been authenticated and some believe it to have been a hoax.
The anonymous letter alleged there was a group of conservative Muslims attempting to usurp school governing bodies.
It has led to investigations by Ofsted, Birmingham City Council, the Department for Education and the Education Funding Agency.
According to the Ministerial Code, ministers "should be able to express their views frankly in the expectation that they can argue freely in private while maintaining a united front when decisions have been reached".
It adds: "This in turn requires that the privacy of opinions expressed in cabinet and ministerial committees, including in correspondence, should be maintained."