Katherine Sciver-Brunt is England women's greatest-ever bowler - Isa Guha

Katherine Sciver-Brunt is the greatest England women's bowler there has ever been, and one of the best the world has ever seen.

She leaves a glittering legacy. I am just in complete awe of what she has done in the game and for English cricket.

To be able to play at the highest level for two decades as a batter is pretty amazing, but to do it as a fast bowler is nothing short of extraordinary.

And on top of that, she was able to lead the attack for her entire tenure.

As a friend, I know just how much she has put her body through and the many times she probably felt like she couldn't carry on, but she always did.

There were some terrible injuries, particularly to her back, so to still be putting in some of her best performances in the past 18 months at the age of 37 is testament to her character, her drive and her determination.

Katherine deserves all the recognition for what has been an absolutely astonishing career.

She has crossed generations, having come from an era when we were amateur, then semi-professional and all the way into the professional age.

Her retirement from playing for England at this time might feel a little bittersweet, because the women's game is on the cusp of something monumental, with its extreme growth and the opportunities that competitions like the Women's Premier League in India are providing now.

And not least, missing a chance to get at the Aussies again - a team that she has always had amazing battles with ever since she burst on to the scene as a 19-year-old.

She might not be able to enjoy the fruits of what women's cricket is about to become, but she can be so proud of all she has achieved and the extraordinary ride that she has been on.

I've been very fortunate to follow her career throughout the years in my broadcasting career, after my own retirement from playing in 2012.

But my fondest memory with her is still winning the Ashes back in 2005. We hadn't beaten Australia in Tests for 42 years and Katherine was named player of the series.

For me, that was when I saw her graduate as an England cricketer.

Suddenly we had our primary weapon - a young tearaway who could strike fear into the Australians.

And together, we had such a fun time that summer.

My favourite moment was our batting partnership in the second Test match at Worcester, at numbers 10 and 11, when we came together with a lead of about 70 and extended it by another 75.

Katherine then bagged another four wickets to add to her five in the first innings, and with a 50 to her name with the bat it was the standout performance of the summer.

We ended up winning that Test and regaining the Ashes, but I remember sharing a room together too, when we were not out overnight.

I just remember us being so giddy and excited about the prospect of walking out to bat the next morning, and the fact that we'd been able to stick it out together against this world-class team.

We absolutely milked it and got the top order giving us throw downs in the warm-up. It is a memory that has always stuck with me.

There have been tough times, too. When she was ruled out of the 2018 T20 World Cup with a back injury, I remember being really concerned about her wellbeing and whether she could carry on.

But she took that time out and worked so hard to get back to peak fitness. She's proved a lot of people wrong throughout her career about how long she could continue for, and it's all been down to her wanting to win for England.

Off the pitch, Katherine has a shy demeanour but when she is comfortable in her environment, she is the loudest person around, with an energy that lifts everyone around her.

She's very charismatic but also quiet and measured at times.

When she crosses that white line, though, she turns into a completely different person.

It's something that we all recognised as team-mates, because it's what she needed to bring out the best in herself.

Sometimes, it was a matter of battling that balance of being fired up, but being able to manage the fire that burned within her.

At times over the past 12 months, and she will be honest with this, it did boil over and she lost control of that perfect state needed to perform at her best.

But that's just her passion pouring through, she cares so much and never wants to let the team down.

It is the pressure that is carried even more when you get towards the end of your career when there is so much at stake, along with the expectations you put on yourself and the team.

It can be incredibly intense, especially when it's played out in front of millions of people - that is something I don't envy about the players these days.

While she didn't get her perfect ending of lifting another trophy, she can be safe in the knowledge that her legacy will live on as the girl from Barnsley who conquered the world.

There will never be another Katherine Sciver-Brunt, but there will be plenty of those who aspire to be.

I look forward to seeing the next generation take it on with a huge opportunity in the Ashes this summer.

Isa Guha was speaking to BBC Sport's Ffion Wynne.