According to the Standard "Market research published by the Mayor's newsletter, The Londoner, claims 140,000 extra passengers would use the late service. If the Tube ran later into the night, trains would have to start an hour later the next morning to allow essential maintenance to be carried out."
I would have thought hardly anyone travelled early on Saturday and Sunday mornings (possibly people who missed their last train the night before and decided to make a whole night/morning of it) but I'm wrong as surveys show that 55,000 catch those early morning milk trains, with almost 60% travelling to and from work (so perhaps the other 40% are people travelling from the night before).
Ken said "We want Londoners to be aware of the advantages and disadvantages of running the Tube later and we want to hear their views before a final decision is made."
Apparently we're going to be polled over the coming months and if the vote goes through the service will change in late 2006.
There's an online vote on The Standard, where, not surprisingly, it's way in favour of extending the hours. I should imagine a fair few mini cab and taxi drivers will be voting against this in their droves.