A coach has been converted into a field hospital at Liverpool Street station in central London to treat revellers who drink too much on Christmas nights out.
In previous years a tent has been put up at the station by London Ambulance Service, but it said the bus would have additional space, including beds for three patients.
An adjacent covered treatment area will hold two more beds.
Last year crews treated 183 patients at the railway station.
The duty officer at the facility, Nick Lesslar, said: "In the run-up to Christmas we see more and more patients who need our help because they've had too much to drink.
"Often the patients we see need time to sober up and that's where the treatment centre can help," he added.
"It means we can keep people who've overdone it away from A&E departments and keep ambulances free for life-threatening emergencies."
Mr Lesslar advised people to eat before consuming alcohol, ensure they drank lots of water and knew how they would be getting home.