[6] Arnott joined UKIP in 2001, and stood in the 2004 and 2009 European elections, being the party's No.2 list candidate in the Yorkshire and the Humber region on both occasions.

Arnott said he wanted to appeal to the millions of voters who did not support UKIP in the previous year's general election but backed Brexit in the EU referendum.

[10] In the general election of 2005 he stood as a UKIP candidate for the Sheffield Attercliffe constituency, coming fourth overall with 4.5% of the vote,[11] losing his deposit.

[15] After the 2015 general election, Arnott accused the party of peddling a "toxic message" and "banging on" about immigration which he said lead to "self-inflicted" disappointing results.

[17] Arnott was one of the most vocal internal critics of the infamous UKIP "breaking point" poster[18] that was unveiled in the run-up to the 2016 EU referendum.

On 12 October 2012, Arnott was announced as the UKIP candidate for the Police and Crime Commissioner elections in South Yorkshire[21] coming fourth with 11.54% of the vote.

[24] On 1 March 2018 Arnott was one of three UK MEPs who voted against a motion to encourage national parliaments to ban "gay conversion therapies".

[25] In June 2017 Arnott published a document called 'Britain Beyond Brexit'[26] which sets out an alternative policy platform and vision for the future of UKIP.

[27] In 2017 UKIP revealed a new 'integration agenda'[28] which proposed the banning of Muslim face-coverings in public, disbanding Sharia councils and physical checks on young girls believed to be at risk of female genital mutilation.

[29] Arnott stated that he had watched recent events with "disappointment, bordering on despair"[30] and warned that the party was heading in a "bland and anti-Muslim" direction.

[4] In his resignation letter, he stated that he had lost confidence in UKIP leader Henry Bolton, who he felt was "not the right person for the job" - but thought no better of those "jockeying" for position in the party.

[42] He has also represented Great Britain at the board game Stratego, helping the British team to the bronze medal at the 2012 World Championships.