Born in Glasgow to an Irish mother and Polish father who died from war-related illness in 1958, MacShane was educated on a Middlesex County scholarship at St Benedict's School, Ealing and studied at Merton College, Oxford.

In November 2012, Labour suspended MacShane when the Standards and Privileges Committee found he had submitted 19 false invoices "plainly intended to deceive" the parliamentary expenses authority.

He was a member of the Deregulation Select Committee 1996–1997, and served as Parliamentary Private Secretary to a succession of ministers in the 1997–2001 Parliament.

[11] Following the 2001 general election, MacShane was appointed Parliamentary Under-Secretary of State for Foreign and Commonwealth Affairs on 11 June 2001,[12] with responsibility for the Balkans and Latin America.

Mahmood's actions were condemned by Inayat Bunglawala from the Muslim Council of Britain, who said that "[after] Lord Ahmed refused, MacShane then found Mahmood—universally regarded as being not exactly the brightest spark in parliament—to be a more willing instrument for his scheme".

[20] During a meeting of Durham Labour Students in 2004, MacShane described Gordon Brown's five economic tests for joining the European single currency as, "a bit of a giant red herring.

"[22] In March 2005, MacShane signed on to the Henry Jackson Society principles, advocating a proactive approach to the spread of liberal democracy across the world, including by military intervention.

[24] While MacShane has campaigned on the issue of sex trafficking,[25] he was accused of repeatedly using false statistics in order to inflate the number of female victims.

In January 2007, he stated, "According to Home Office estimates, 25,000 sex slaves currently work in the massage parlours and brothels of Britain."

for wrongly accusing London School of Economics professor of political and gender theory Anne Phillips of supporting prostitution and filling the minds of her students with "poisonous drivel".

As evidence of her supposed support for the latter, he cited a question from an LSE reading list about the ethical differences between legal waged labour and prostitution.

[29] Labour MP Fiona Mactaggart subsequently called Professor Phillips' views "frankly nauseating" on the basis of the same evidence.

Saying that he had done too little, he said he had been aware of what he saw as the problems of cousin marriage and the oppression of women within parts of the Muslim community in Britain, but: "Perhaps yes, as a true Guardian reader, and liberal leftie, I suppose I didn't want to raise that too hard.

[36] MacShane was an advisory board member of the now defunct Just Journalism,[37][non-primary source needed] an organisation focused on how UK media reported Israel and the Middle East.

[39][40] He was also alleged to have passed twelve invoices from the "European Policy Institute" for "research and translation" expenses to the parliamentary authorities, and claimed for eight laptop computers in three years.

[46] He said: "I have decided for the sake of my wonderful constituency of Rotherham and my beloved Labour Party to resign as an MP by applying for the Chiltern Hundreds or as guided by the House authorities.

[47] He said in a statement: "Clearly I deeply regret that the way I chose to be reimbursed for costs related to my work in Europe and in combating antisemitism, including being the Prime Minister's personal envoy, has been judged so harshly.

[52] In June 2011, The Daily Telegraph highlighted further discrepancies in MacShane's expenses which had been uncovered by former independent candidate Peter Thirlwall.

[55] On 11 July 2013 the Crown Prosecution Service announced that MacShane would be charged with false accounting under the Theft Act 1968, involving the creation of £12,900 of fake receipts.

[61] After MacShane was forced to resign his seat, Martin Bright in The Jewish Chronicle wrote that his "fall from grace has been a blow for those who share his concerns about extremist politics, whether it is radical Islamism in the Middle East, neo-fascism at home or the rise of ultranationalist groups in Eastern Europe.

[63] Shortly after being released from prison in 2014, UKIP MEPs alleged MacShane was ejected from the premises of the European Parliament members' bar where he had been meeting UKIP leader Nigel Farage, after a British MEP accused him of loitering in the building "like a bad smell" and told officials he had no right to be there.

[65] He has written more than ten books on European politics including three on Brexit about which he writes and broadcasts regularly in Britain and Europe.

His follow-up book, Brexiternity: The Uncertain Fate of Britain, argues that Brexit will dominate British politics, economics and international relations for years to come.