The UK government has signed deals for a further 90 million doses of coronavirus vaccine, Report says, citing TASS.
The vaccines are being developed by the Belgian pharmaceutical company Janssen and the US biotech company Novavax.
It means the UK has placed orders for six experimental vaccines, taking its potential stockpile to 340 million doses.
In theory, there should be enough for everyone in the UK to get five doses. Most of the vaccines require only two.
With most vaccine trials failing, the government is effectively hedging its bets, hoping that at least one of the vaccines it has purchased is safe and effective.
Kate Bingham, chair of the UK government Vaccine Taskforce, told the BBC: "We don't know if any of these vaccine formats that we've acquired will work. There are no licensed vaccines for any human coronavirus."
She added it was a "priority" to ensure the UK has "sufficient vaccine" for groups "who are most at risk from coronavirus infection."
It takes Britain's potential stockpile to a total of 340 million doses, one of the world's biggest.
The government says if the Janssen and Novavax vaccine trials go well, the first deliveries could occur in mid-2021.
The UK has also agreed to co-fund a clinical study of the Janssen vaccine.