Labour's Simon Danczuk suspended over 'inappropriate behaviour'
Labour MP Simon Danczuk has been suspended by the party after newspaper allegations about his private life.
The Sun alleged he exchanged explicit messages with a 17-year-old girl.
On Twitter, the Rochdale MP said the story was "not entirely accurate" but referred to "an extremely low point" in his life.
He said he apologised unreservedly for his "inappropriate" behaviour, adding: "I was stupid [and] there's no fool like an old fool."
A Labour Party spokesman said: "The general secretary of the Labour Party has today suspended Simon Danczuk's membership of the party, pending an investigation into allegations published in the media today.
"A full investigation will now take place under the authority of the National Executive Committee, which will be responsible for determining any further action."
Mr Danczuk, who separated from his wife earlier this year, has been the MP for Rochdale since 2010.
The backbencher has been a strong critic of Labour leader Jeremy Corbyn and his predecessor Ed Miliband, and has carried out a high-profile campaign to expose historical child abuse.
In his statement on Twitter, he added: "I'm more saddened that this episode could overshadow the important work we're doing to help Rochdale [and] that's where my focus lies."
Simon Danczuk profile
The Rochdale MP has a reputation as an outspoken backbencher. He has been a thorn in Jeremy Corbyn's side and has described his predecessor Ed Miliband as "one of the worst Labour Party leaders in history".
The 49-year-old is perhaps best known for his campaigning work on historical child sex abuse, having co-authored a book on alleged abuse by former Rochdale MP Cyril Smith and called for action over a missing 1980s dossier about alleged paedophiles at Westminster.
In July, he said he was stepping back from his child abuse campaigning work to seek help for depression, adding that he was "in no doubt" it had taken its toll on his marriage.
As a consequence of his suspension, Mr Danczuk has had the Labour whip withdrawn, meaning he will sit as an independent MP.
Although the girl featured in The Sun was over the age of consent, BBC political correspondent Chris Mason said the allegations were particularly embarrassing for an MP who had devoted much of his time in recent years to campaigning about child protection.
In interviews, Labour leader Jeremy Corbyn and shadow chancellor John McDonnell both stressed the independence of the National Executive Committee (NEC) investigation.
Corbyn ally and NEC member Ken Livingstone told the BBC people should not jump to conclusions based on Mr Danczuk's suspension.
"We won't be rushing to any judgement," he said.
The party clearly had to investigate the allegations, he said, adding: "The simple fact is that it might not be illegal but a lot of people are going to disapprove of that sort of age gap and that sort of texting, particularly given this is an MP who made the exposure of child abuse a key part of his political career."