In 2012, Marsden was appointed to draft the parliamentary inquiry report into VIP security at the Olympic and Paralympic Games in London.
Marsden is currently Head of Quality for the Transpennine Route Upgrade West rail alliance, improving the railway between Manchester and Leeds.
[17][18] The Guardian in its Leader praised Marsden for having called for a vote on the war and publishing the Chief Whip's response to it and stated, "On both counts he has done British democracy a service.
"[19] Undeterred by the Whip's criticism, Marsden then spoke out against the press officer Jo Moore who had said, that 9/11 was "a very good day to get out anything we want to bury"; he and Tam Dalyell were the only two Labour MPs to vote against the Government.
[22] Marsden also negotiated the release of Sunday Telegraph journalist Christina Lamb and photographer Justin Sutcliffe, who had been arrested and held by the Pakistan Police and Inter-Services Intelligence secret service.
[27] Marsden complained bitterly that he had been subjected to late night physical attacks by some Labour Whips, which were vigorously denied.
[28][29] Five days later, he defected to the Liberal Democrats on 10 December 2001, citing his disagreements with Labour whips over his opposition to military action in Afghanistan and the resulting civilian casualties.
His accusations that the failures of the International Monetary Fund had exacerbated the famine caused a public argument with the IMF Director.
Marsden strongly opposed the war in Iraq and repeatedly voted for an inquiry into the alleged intelligence failings and concerns that parliament was misled.
He reduced his Liberal Democrat political duties and on 5 April 2005, within hours of the start of the election campaign, Marsden announced his intention to rejoin the Labour Party, stating that although he still disagreed with the government over the war and levels of investment in public services, he did not want Labour MPs, who shared his views, to lose their seats.
He was the first British politician since Winston Churchill to re-cross the floor of the House of Commons and return to his original party, in Marsden's case to sit on the Labour benches.
[1] During his Parliamentary career Marsden raised over £10K for local and international charities through sponsored marathon running, abseiling and swimming.
[44] In the 2005 general election the Conservative, Daniel Kawczynski won back the Shrewsbury and Atcham seat from the subsequent Labour candidate, Michael Ion.
Sir Thomas Legg gave Marsden a clean bill of health and reported that he was one of only a minority of MPs and ex-MPs with "no issues".
In 2007, Marsden was appointed Director of Policy at the British Union for the Abolition of Vivisection[48] and between 2008 and 2010 was the CEO of the Painting and Decorating Association.
[50] A Channel 4 Dispatches programme interviewed Marsden and it was revealed that the reporter in question, had been suspended for phone hacking, although he denied it.
[51] In May 2011, Marsden wrote on his Blog, www.paulwbmarsden.blogspot.com,[52] an article about the debate on public interest vs privacy in which he mentioned the allegations that Ryan Giggs was the footballer who had taken out a super injunction against Imogen Thomas.