1 of 16
Last week Ken Livingstone offered �100,000 for an idea which would cool the Tube. Here are the best of your ideas.

2 of 16
Richard Miller of London offers a simple idea - open top carriages.

3 of 16
Aled Powell: "Simply re-decorate the stations to make commuters feel like they need their winter woolies in summer."

4 of 16
Andy Glynn: "Print maps on flame retardant paper. Passengers concertina their maps and have a handy fold-up fan."

5 of 16
Ed Shore: "Insert coils of pipe in seats, and then put cold water through them. Use the same technique on hand rails."

6 of 16
Giles Hogben: "You have a tank of water for each train. At each station, you pump water out and cold water in."

7 of 16
Harry Sabbers: "This would be both cheap to produce, requiring only water and flavoured syrup, and would be totally delicious."

8 of 16
John Cusick: "Ice. Make the train a freezer while it makes human popsicles."

9 of 16
Joseph Yiu: "Have water curtains. Different coloured lights can be artistic. People will be calmed when trains don't arrive."

10 of 16
Josh Bentley: "Crank up the power on the London Eye, and make it an oversized fan."

11 of 16
Julian Burgess: "Replace tired old tracks and trains with canals and gondolas, the slow pace of travel will make it pleasant."

12 of 16
Mark Coates: "Put up posters of wintry themes on the walls, snowmen and the like, it's all in the mind you know."

13 of 16
Nigel Wilkinson: "A heat curtain would mean trains would stop cooled air going into the tunnels."

14 of 16
Omri Stephenson: "This solution could also be a promotional tie-in with a frozen food company. How can it fail?"

15 of 16
Phil Fanning: "Use the Thames as a cooling medium."

16 of 16
You sent in more than 2,000 ideas, many much more serious than those we have shown. We have sent them all to Ken Livingstone.