Get in the toilet queue well ahead of time

3. Eat a normal but not huge meal, mainly of carbohydrates (pasta, rice, potatoes) the night before, and drink plenty of water.

4. Get an early night, but don't worry if you don't sleep. As long as your body gets eight hours horizontal, it will be rested.

Race day:

5. Plan to reach the start one hour ahead of time, allowing for the fact that underground trains are packed and the walk up to the start takes about 10 minutes.

6. Get in the toilet queue well ahead of time - you could be there for 10 minutes.
If it is warm, take a good drink just before the race starts, but not half an hour before, because it will make you want to pee again.

7. Check the exact location of the start and find your correct pen.

8. If you are going for a time, write down the planned time for every three miles, on the inside of your forearm

9. Confirm your arrangements for meeting friends afterwards, and have a fall-back plan if you don't meet - the crowds are incredible.

10. Tell yourself it is going to be fun, tough but FUN with a capital F!