Doctors in the West Midlands have been told to plan for a mass coronavirus vaccination scheme from as early as November.
A leaked document identifies two vaccines which are expected to be available this year.
Immunising the entire population could take 10 months and will start with the most vulnerable in care homes.
Mass vaccination sites and mobile facilities are being commissioned as part of as a "fairly massive exercise".
According to the document, the two vaccines are called Ambush and Triumph.
Ambush needs to be stored at -70C (-94F) and kept in hospitals due to regulations set down by the Medicines Health Regulatory Authority.
The Triumph vaccine is expected to be the one developed by Oxford University and AstraZeneca, which can be stored at room temperature.
The document says the vaccines will have to be given in two doses, 28 days apart - and this will be dependent on supply.
Speaking earlier at a Birmingham City Council Covid-19 engagement board, Paul Jennings, Chief Executive of Birmingham and Solihull Clinical Commissioning Group (CCG), said 800,000 people would be prioritised in any rollout.
He said planning for the rollout had already begun, according to the Local Democracy Reporting Service.
'Pretty massive population'
The CCG covers a population of some 1.3 million people and Mr Jennings said the immunisation programme would be "unprecedented".
"I understand the target groups will be the over 65s and vulnerable, the 50-64s who have some other feature than their age, and anyone of a BME background over the age of 18, so that's a pretty massive population for us to be thinking about," he said.
The national plan talks of focusing on care home residents and staff first and then starting with the over 80s before descending in five-year tranches to 65.
High-risk adults under 65 and all those down to 50 would then take priority ahead of the rest of the population.
It is possible that volunteers will be called upon to undertake non clinical roles because of the sheer scale of the exercise.
Two mass vaccination centres will also be created in Herefordshire, the BBC has heard.
About 140,000 doses are expected to be delivered to Herefordshire and Worcestershire in 14 weeks.
Staffordshire is set to receive 600,000 doses and one of the vaccines is being manufactured locally at Keele University.