Last things last...

I'll let you get your breath back: time travelling Kate Orman style is a wonderfully exhausting business. So, are you sitting comfortably? Then I'll finish.

Doesn't time have a habit of doing peculiar things? It's five years since the Doctor and Ace walked off the screen to that great cup of tea in the sky; four years since the TARDIS materialized in print in Mesopotamia, and John Peel asked me to write the foreword for the first New Adventures novel.

I felt then that I should never be allowed to leave the Doctor Who family, and although here we are now, with Ace adventured out on videotape and now in ink, I feel more than ever before that this Doctor Who thing is for life. I can't get away from Ace even if I wanted to, and I don't.

People have asked me what it's like to read about Ace in the New Adventures. It's been like standing on a crowded tube station platform, and catching a glimpse of someone who was once very dear to me, in the flickering half- light of a through train. Mind the gap, that ever widening gap. For now it's time to move on again.

There's a part of me that hates goodbyes, and it's my second goodbye to Ace. Which reminds me of that day back in October 1990 when the phone rang for me at the BBC North Acton rehearsal rooms and Sylvester was on the other end of the line.

‘Are you sitting down?’ he suggested. ‘I've got some bad news – they've cancelled Doctor Who.’ He may as well have told me they'd cancelled next year. I put a brave face over the hurt one and went back to the all-singing, all-laughing Corners rehearsals, saving my tears of disappointment for a more private moment.

And now it's goodbye, and I should be used to it by now. Kate has done us proud. Here's an Ace I would love to have played on screen: older, wiser, battle-scarred and feisty as ever. And the lump in my throat this time is for the end of the relationship between the Doctor and Ace, so touchingly portrayed here and just as I would have wanted in the TV series. My thanks to all the New Adventures writers for taking Ace to new pastures and new extremes, and also to all Ace fans who have followed her to the ends of time and back. Yes, it's time for a rest, and time for the Doctor to be called something other than Professor. So. That's all folks. Or is it? ‘Time will tell; it always does.’