Tristan and I have embarked on a crazy challenge to raise money for Macmillan Cancer Support.

We will be walking the entire length of the London Underground map (overground), one line at a time and calling at all the stops.

To give you an idea of the sheer stupidity of the task at hand, that involves 11 tube lines, 270 stops, 380 miles of walking and 800,000 steps!

I've personally been affected by cancer and have people close to me who have also fought the disease. We all know someone who has been touched by it. Macmillan Cancer Support offers all types of support: Trained Macmillan nurses, financial support in the form of grants and benefits advice, a helpline, website, leaflets and much more so that those with cancer feel supported.

We can update you on our progress as we're recording our routes with GPS.

So far we have done:

The Victoria Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20130616-1117?r=x

The Bakerloo Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20130630-1427?r=s

The Waterloo and City Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20130720-1232?r=s

The Circle Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20130728-1115?r=s

The Jubilee Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20130824-1106?r=x

The Northern Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20130914-0914?r=x

The Hammersmith and City Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20130929-1027?r=x

The District Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20131026-0914?r=x

The Central Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20140111-0926?r=x

The Piccadilly Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20140111-0926?r=x

The Metropolitan Line: http://runmeter.com/fdc28e1ea3ac2874/Walk-20140308-0850?r=s

All the lines completed: http://goo.gl/maps/G5IdW

It's only going to get harder (that 40-odd mile Central Line is a beast!) so please help spur us on with your donations!

Donating through JustGiving is simple, fast and totally secure. Your details are safe with JustGiving – they’ll never sell them on or send unwanted emails. Once you donate, they’ll send your money directly to the charity. So it’s the most efficient way to donate – saving time and cutting costs for the charity.

So please dig deep and donate now. You can keep an eye on our progress at our Facebook page linked to below: https://www.facebook.com/CatAndTristansLondonUndergroundOvergroundWalk?hc_location=stream