A police investigation has been launched after a death threat aimed at controversial MP George Galloway was sent to the Houses of Parliament.
Officers from the Palace of Westminster contacted the Metropolitan Police's Counter Terrorism Command following the receipt of the letter yesterday.
According to a source, the letter included a threat that the Respect Party MP would "die from a deadly virus".
Scotland Yard tonight said the letter intended for a member of the House of Commons and was being treated as "malicious communications".
Controversial Respect MP George Galloway was badly bruised after he was attacked in the street tonight, his spokesman said.
Mr Galloway was posing for pictures with people in Notting Hill, west London, when the incident happened.
The spokesman said: "George was posing for pictures with people and this guy just attacked him, leapt on him and started punching him.
"It appears to be connected with his comments about Israel because the guy was shouting about the Holocaust.
"George is badly bruised but OK. He has bruising to his head and face and is in a pretty bad shape."
Metropolitan Police said a man had been arrested on suspicion of ABH and taken to the south London police station where he remains.
The motivation for the attack is unclear but Mr Galloway caused recent offence when he announced Bradford was an "Israeli-free area".
Respect MP George Galloway has been interviewed under caution by police after making a speech in which he announced Bradford was an "Israel-free zone".
The left-wing MP stated in the speech that Israelis were not welcome in the city where he has a constituency.
West Yorkshire Police said it would investigate after footage of the speech, made in Leeds, circulated online.
He has now been interviewed voluntarily and the Crown Prosecution Service will decide whether any charges should follow.
Police have launched an investigation after Respect MP George Galloway declared Bradford an "Israel free zone" during a speech.
The speech caused outcry on social media after being posted online. Mr Galloway was filmed saying:
West Yorkshire Police said it was investigating his comments, which relate to the city where Mr Galloway has a constituency.
A force spokesman said: "We have received two separate complaints about comments attributed to George Galloway MP during a speech he gave at a public meeting in Leeds on August 2. We are currently investigating the complaints."
Respect MP George Galloway has told the House of Commons that issue of determining if the Assad regime was responsible for any chemical weapons attacks is based on the idea: "not that they are bad enough to do it, everyone knows they're bad enough to do it but is he mad enough to do it."
Mr Galloway went on: "To launch a chemical weapons attack in Damascus on the very day that a United Nations chemical weapons inspection team arrives in Damascus must be a new definition of madness.
"And of course if he is that mad, how mad is he going to be once we've launched a blizzard of tomahawk missiles upon his country?"
MPs will debate later today whether Wednesday's Prime Minister's Questions session should be cancelled so members of the Commons can attend Baroness Thatcher's funeral
George Galloway and Labour veteran Dennis Skinner objected to a motion that would have allowed the chamber's sitting times to be altered.
The pair's cry of "object" means the proposed change will now be voted on after a debate lasting up to three hours.
Mr Galloway described Lady Thatcher as "a wicked and divisive woman" who did "great damage to a society she said didn't exist".
Mr Galloway said, "People think the canonisation of Lady Thatcher has gone on long enough. The muffling of the chimes of Big Ben is a step too far and now Mr Cameron will miss Prime Minister's Questions for four weeks. It is unconscionable".
George Galloway will try and block Government plans to cancel Wednesday's Prime Minister's Questions session to allow MPs to attend Baroness Thatcher's funeral.
The Respect MP said he will call "object" when the motion to delay the start of parliamentary business until 2:30pm is brought before the Commons tomorrow night.
Ministers hoped the motion, tabled by the Leader of the House Andrew Lansley, would go through "on the nod".
Mr Galloway said he will take advantage of Commons rules which mean if one MP shouts "object" the motion will either have to be withdrawn - allowing PMQs to go ahead as normal - or the Government will have set aside parliamentary time on Tuesday so that it can be debated and then voted on.
"It really is imperative that the Prime Minister is questioned, among other things, about his decision to impose a quite unnecessary and expensive early return of Parliament which was simply a hideous outpouring of right-wing eulogies and rants doused in crocodile tears," he wrote on his website.
"I'm glad to see that, like me, more than a hundred Labour MPs stayed away from the circus".
MP George Galloway has missed 87% of all Commons votes during his first year as a Bradford MP and spoken in just seven debates.
Data compiled on website theyworkforyou.com show Mr Galloway has taken part in just 13% of the votes over the past year. Most MPs average between 70 and 80%.
He has spoken in just seven debates - the average for MPs being around 30.
Mr Galloway, a member of the Respect party, has declared the figures "fundamentally flawed" as they present only a partial picture of what an MP does. His office said he has tabled dozens of motions, written letters to Ministers and dealt with a large amount of constituency work from his office.
The Respect MP George Galloway has paid tribute to Hugo Chavez, calling him a "modern day Spartacus" and a "champion of the poor":
Respect MP for Bradford West, Geoge Galloway, has taken to Twitter to deny that he was the Caped Crusader who handed in a man to police in the northern city: