There’s an unwritten rule in sports journalism: never cross the line into fan territory.

But some people are worth breaking the rules for.

My first memory of watching Paula Radcliffe run was probably in 1999 at that year’s World Championships. I’d become full-on obsessed with athletics the previous summer at the age of 13, so I remember being glued to the TV for all of the action from Seville.

As a British fan, you couldn’t help but root for Radcliffe; a committed front-runner who visibly gave it everything she could and left nothing on the track. Her best on that occasion resulted in a silver medal. You could just sense, though, that there was more to come; it simply wasn’t in Radcliffe’s character to settle for second-best.

She – and we, as fans – only had to wait little more than a year before she won her first senior global title. Radcliffe’s move up in distance paid off handsomely and she won the world half-marathon title in 2000. It was to be the first of three gold medals she won at that event over the next few years.

During that time, she also achieved one of her other major goals: winning the world cross-country title. She did it twice for good measure, taking golds in 2001 and 2002.

No longer was she the ‘plucky loser’ who ‘bravely’ took on the Africans before being out-kicked. She was a bona fide champion. Several times over. Undisputed.

But perhaps her best performance – the one for which she will be remembered for years to come – didn’t come in a championship setting. I could write a whole separate blog post about how great her marathon world record of 2:15:25 is (in fact I have; here it is). Suffice to say, it is bloody phenomenal.

I remember watching it at home in sheer awe and complete disbelief. But looking back, even then I don’t think I was fully aware of just how incredible the performance was. Sometimes only the passage of time can give you a true appreciation of things. This was one such instance.

After her 2003 London Marathon victory, the following decade of her career saw more ups and downs than one of her hill runs in Font Romeu. She won two more world titles, one at the half marathon in 2003 and one at the marathon in 2005, but also had to deal with Olympic heartbreak three times over, in 2004, 2008 and 2012.

I’m not going to go into those. Lord knows, in the aftermath of the Athens Olympics, I got into so many debates on online forums (“SHE’S NOT A QUITTER!”, “IT HAD NOTHING TO DO WITH THE HEAT!”, etc) that I probably ended up writing more on that subject than I did for my university thesis that I was working on at the time.

Needless to say, those Olympic misfortunes have definitely not defined her career. All of Radcliffe’s other achievements – the world records, the six global titles, the European and Commonwealth gold medals – by far outweigh Nouriah Merah-Benida’s medal cabinet (no disrespect to the Algerian, but if you had to Google her then it kind of illustrates my point).

I have been fortunate enough to work with Radcliffe when creating her official website more than a decade ago. I’ve had the honour of interviewing her following her triumph at the 2005 World Championships. More than that, though, I’ve had the privilege of following her career as an athletics enthusiast. And what a career it has been.

On Sunday, Radcliffe will run her last competitive marathon. In many ways, she is coming full circle. Back in the city where she set her legendary world record; the city in which she has won three times; the city which hosted what should have been her last shot at the Olympics. And back on the start line with the club runners, where Radcliffe’s career began back in the early 1990s.

This time, I’m not going to watch it on TV at home, nor will I be reporting on it in my capacity as a sports writer. Instead, I’m going to join the thousands of people lining the streets of London and, just as I did as a spotty teenager tuning into the 1999 World Championships, I’m going to cheer on Radcliffe as a fan.

To hell with the rules.