Police are now investigating three separate allegations of death threats from an antisemitic Twitter stalker who advertised himself as an Ed Miliband lookalike.

Shereef Abdallah first targeted a young woman who runs the Julie's Think Tank blog, which supports liberal intervention in the Middle East. He later threatened a former Labour Party press officer who came to her defence online, and a young British-Israeli woman who challenged him on his use of the word "Nazi" to describe people who disagreed with him.

The Labour Party has suspended Mr Abdallah's membership as a result.

The Metropolitan Police said: "Officers from the London Borough of Camden are investigating a possible case of 'malicious communication', following allegations of antisemitic comments being placed on Twitter. The victim, a 32-year-old woman, received several threatening messages between November 2011 and January of this year."

A spokesman said: "Officers believe there may be further victims, and enquiries continue."

Labour Party suspends his membership as a result of 'cyberstalk'

Police later issued a statement that read: “A man in his late 30's, arrested on 17 January by officers from Camden investigating death threats antisemitic comments being placed on Twitter has been released with no further action.

"The man had been due back on bail in April pending further enquiries. A report was submitted by police to the CPS for consideration. The CPS concluded there was insufficient evidence to provide a realistic prospect of conviction. There is no further action by police”.