Getting home after an evening out in London could be easier if plans to run Tubes an hour later on Friday and Saturday nights get the go ahead.
Late-night Tubes could begin in December 2006
But later night-time hours would shut the network for an extra hour on Saturday and Sunday mornings, which could hit weekend workers.
Transport for London (TfL) says this is because the same amount of time will be needed for overnight maintenance work.
A two-month public consultation on the plan begins on Tuesday.
Research by TfL shows that around 55,000 people currently use the Tube during the first hour of operation over the weekend.
If the Tube runs until 2am it will not start until 7am on Saturday and 8.30am on Sunday.
HOW YOU CAN HAVE YOUR SAY
On the TfL website - www.tfl.gov.uk
On a freephone helpline 0800 10 60 22 (textphone 0800 10 60 27)
Or you can fill out a leaflet available at all London Underground stations
Mayor of London Ken Livingstone said: "A later running Tube would help thousands of people to get home safely and conveniently after a Friday or Saturday night out.
"Many passengers say they would spend more evenings out in the capital if they could get home on the Tube."
Tim O'Toole, London Underground, said: "The Tube is improving, but for that to continue, it is essential that we retain the same number of hours for essential maintenance and renewal work."
Brian Cooke, of London Transport Users Committee, said: "There definitely are upsides and downsides that will benefit a lot of people late at night.
"But people will be inconvenienced in the early morning, and we are concerned that some of those people are essential workers and people on low incomes who have to get to work."
If the idea gets the go-ahead the new timetable could come into force in December next year.