Allies of Matthew Elliott view him as a noble crusader against government waste. Opponents see him as a shadowy figure pushing a dangerously right-wing agenda.
But few would disagree that the Tax-Payers' Alliance chief executive and No to AV campaign mastermind is one of the most successful political campaigners in Westminster today.
With Elliott at the helm, the TPA has become arguably the most influential political campaign group in the UK, pumping out regular stories of 'shocking' public sector waste and scoring dozens of media mentions every week.
Elliott, 33, has also set up a second lobbying group, Big Brother Watch, to 'roll back a decade of state interference in our lives'. Earlier this year, he took a sabbatical to run the campaign against the alternative vote. When 67.9 per cent of voters came out against a change to the voting system on 6 May, David Cameron breathed a sigh of relief - and Elliott's stock soared to new levels.
'At the moment, he's there at the very top of centre-right campaigners in Britain,' says Tim Montgomerie, the leading Conservative blogger. 'He does all the things that a successful campaigner needs to do. He has message discipline, he takes opinion research incredibly seriously, he's intelligent and works hard.'
For the boss of rather a 'shouty' pressure group, Elliott is also remarkably mild-mannered. The TPA is adept at winding up councils and quangos, but its chief executive could not be more courteous. If Elliott is a political fighter, he may just be the most polite man on the battlefield.
It is now eight years since Elliott began his war against waste. At the time, Gordon Brown, as chancellor, was investing heavily in public services and the Conservatives were not opposing Labour's spending plans. Elliott says: 'I felt there was a real niche there for a force in British politics to say "hang on, is this money being well spent?"'
Elliott teamed up with pals Andrew Allum and Florence Heath (now his wife), and by 2004 the TPA was up and running - out of Elliott's bedroom in Wood Green.
From the outset, Elliott was working long hours and placing a premium on effective media relations: 'We didn't have an office structure or telephones, so we had a media mobile. At that point, we were the only think-tank or campaign in Westminster that had that sort of dedicated out-of-office number.
'It was just recognising that you can't be a significant group in Westminster and work on a 9.30 to 5.00 basis. If you want to get on the Today programme, you need to be around to have that 1am phone call.'
These days, the TPA resides in somewhat grander premises in the quiet back streets of Westminster, minutes away from the Houses of Parliament, but much of the original operation is intact.
The group retains the same media mobile number it had back in 2004 and Elliott remains committed as ever to giving journalists what they need: 'It's basically about having very good access for them, treating them as professionals and always getting a quote back to them within 15 minutes by email.'
The numerous framed front pages in the TPA offices are clear evidence that the approach is working, particularly with The Sun, Mail, Express and Telegraph - the 'fab four', as Elliott describes them.
But not everyone is impressed. In 2009, John Prescott, the former deputy prime minister, launched a Labour fightback against the growing influence of the TPA, noting its links to Tory donors and alleging that it is 'nothing but a front for the Conservative Party'. Elliott shrugs off the charge: 'Often it's the Conservative councils that are the most wasteful when it comes to excessive salaries and we haven't been afraid to publicise any of that.'
In all of his campaigning, Elliott has not shied away from controversy. The No to AV campaign was criticised for suggesting that implementing the alternative voting system would suck £250m from the NHS and the armed forces.
While opponents claimed the figure was misleading, Elliott stands by it. More broadly, he opines: 'People are not interested in the intricacies of the different electoral systems. We needed some simple messaging that would actually explain it to people.'
After his success on the No to AV campaign, Elliott is hot property in Westminster. Some Conservatives believe he could run the party's next general election campaign. Would he be interested?
Ever the gentleman, Elliott stresses his 'immense admiration' for those running Conservative campaign headquarters. But he emphatically does not rule it out.
2011 Campaign director, No to AV
2009 Founder, Big Brother Watch
2004 Founder, The TaxPayers' Alliance
2001 Political secretary to Timothy Kirkhope MEP
2000 Press officer, European Foundation
MATTHEW ELLIOTT's turning points
What was your biggest career break?
The No to AV referendum, where the campaigning skills I had learned at The TaxPayers' Alliance were put to the test in the ballot box.
Have you had a notable mentor?
The inspiration for setting up a taxpayers' campaign group came from seeing how Business for Sterling/the No Euro campaign transformed Eurosceptic campaigning in Britain. I still greatly value the advice that Nick Herbert, George Eustice and Dom Cummings give me on my campaigns.
What advice would you give someone climbing the career ladder?
Take risks. I gave up my full-time job in Parliament when I had raised enough money to cover my salary for three months at the TPA. Our financial position was sometimes touch and go in the early days, but I have never looked back since.
What qualities do you prize in new recruits?
Hard work. For too long, Westminster groups considered their working day to be 10am to 5pm, when it should be a 24/7 job. Hard work during the day and networking at night is the key to success.