'I like young new challengers,' she says. 'What attracted me to Five is I like small organisations, and while it is seven years old, in TV terms that's still quite new.'
It's a sentiment that explains her involvement with the SDP, which shook up the political scene when it broke away from the Labour Party in 1981, where she was secretary to its parliamentary committee and press secretary to party leader Dr David Owen MP.
Robertson has retained a passion for politics and is proud of the party's legacy, but politics is not exactly in her blood: 'My mother was an air stewardess, my father was a flight engineer, and my sister is an abstract artist!'
Five has presented Robertson with new challenges, although they have largely been in the regulatory field - until now. Next month she will also take over responsibility for publicity after marketing chief David Pullan joins Emap as FHM worldwide MD.
Robertson's student days saw her writing 'Sue's Problem Page' in a Bristol University magazine. This brought her to the attention of NUS leaders who drew her into the world of politics, the British Youth Council and the SDP.
Personalities seem to play a big part in her attraction to politics, and she names a string of characters who played a role in her political growth and who continue to colour the political landscape - Peter Mandelson, Trevor Phillips, Charles Kennedy: 'Alastair Campbell was a reporter on The Mirror when I was at the SDP - these are all people I know.'
Channel 4 deputy head of corporate relations Martin Stott, whose relationship with Robertson stretches back to the SDP and who will join her at Five next month, says: 'Sue knows a lot of people across politics and the media and is extremely well connected.'
Channel 4 deputy head of press and publicity Yvonne Taylor says: 'She is very politically astute and sharp, but she is also incredibly charming - she charms you into doing what she wants. However, she is the least controlling manager I've ever had.'
Her connections and charm have enabled her to chart an unplanned path through her career, beginning with her spell in student politics and continuing when she jumped from production to corporate duties. After eight years producing at the BBC, Robertson's inauguration into popular culture came at Channel 4 as head of corporate affairs.
'I never have a day when I won't listen to Today and I'll watch Five News as well as later news programmes such as Newsnight,' she says. 'But the great thing since I left the BBC is that I've learnt about other genres.
'Five has been very successful with its football coverage,' she says.
'So I've found myself watching football and enjoying it, but my roots are in current affairs.'
At Channel 4, she claims to have grasped the complexities of cricket and 'girlie programmes', but she left to give herself a lesson in 'actual business'. She certainly experienced this during a short year at United Broadcasting and Entertainment where she sunk her teeth into unsuccessfully pushing a merger with Carlton past regulators, only for Granada to swallow United up.
On her expanded publicity role, she says: 'I love the creative world; it's exciting because you never know what you're going to end up with until it's transmitted. The biggest change for me was moving from producing to being a commissioner of programmes. I couldn't believe how quiet the office was. In production, it's all hands on deck and I did miss that.'
Perhaps this is why Robertson enjoys working for the underdog. Five certainly has a battle on its hands with ITV's increased scale following the Carlton and Granada merger, and the papers are filled with merger rumours as Five looks to compete in a multi-channel environment. 'Regulators need to look after the smaller players as well. To have that diversity is a good thing, but we will need some help along the way,' she says. 'One of the good things about press and PR is you never know what will happen.'
Five, with its host of rumoured merger partners, provides Robertson with the unpredictability that attracts her. If she knows which way Five would like to lean, she's not giving anything away.
1977: Vice-president, National Union of Students
1980: Assistant general secretary, British Youth Council
1982-87: Secretary to parliamentary committee, SDP
1983-87: Press secretary to Dr David Owen MP, SDP
1987: Producer, BBC
1995: Head of corporate affairs, Channel 4
1999: Director of corporate affairs, United Broadcasting and
2001: Director of corporate affairs, Five