The plan is simple: spend a day cycling up Swain's Lane and then down Highgate West Hill, doing as many circuits as possible. My record is 11 but I've never spent a whole day doing it.

Swain's Lane is short (1.2km) but steep - 18% in places (that's 1 in 5.5 roughly, or about 10 degrees) - and each ascent is an 87m height gain. Correction: 78m.

To make things more interesting: correctly predict the number of ascents I can do (I have a personal target but it's a secret and if I can beat it I will) and I will donate £50 to the good cause of your choice. The tiebreaker is: closest guess of how many calories I burn (as estimated by Strava). One entry per person per cause donated to, and you have to donate to qualify. If you donate to both causes you get two entries. You have to make your predictions by midnight on Friday 26 September.

Please donate to either or both causes. I will be posting updates on Facebook during the event, and anyone who wants to ride with me, or support me on the day is welcome.

REFUGE
Supports women and children (and men) who are victims of domestic violence and abuse be that physical, emotional or sexual.

AMNESTY INTERNATIONAL
Campaigns for human rights across the world, and stands up for political prisoners, is against torture and judicial murder (aka the death penalty).