The campaign succeeded in retaining pound sterling, forcing the (pro-Euro) Prime Minister, Tony Blair, to keep to his Chancellor of the Exchequer Gordon Brown's five economic tests.

It was also instrumental in persuading the Conservative Party to include a "save the pound" pledge in their manifesto for the 2001 general election.

[5] Herbert unsuccessfully contested the Northumberland seat of Berwick-upon-Tweed at the 1997 general election where he finished in third place some 8,951 votes behind the veteran Liberal Democrat MP Alan Beith.

His selection to contest the safely Conservative West Sussex seat of Arundel and South Downs at the 2005 general election did not come about without incident.

After David Cameron became leader of the Conservative Party, Herbert was appointed as a Shadow Minister for home affairs on 16 December 2005.

[16] Herbert decided to step down from Government at the time of David Cameron's first major reshuffle in September 2012.

[24] In January 2016, Herbert launched Conservatives for Reform in Europe, a campaign to remain in the European Union, subject to the Prime Minister's renegotiations.

[26] In November 2019, Herbert announced his resignation as MP in order to focus on his other campaign roles on rural issues, central governance reform, combatting tuberculosis and securing LGBT rights worldwide.

[27] In the morning of 1 September 2020 he was created Baron Herbert of South Downs, of Arundel in the County of West Sussex.