EU's health chief pressured AstraZeneca to drop its "first come, first served" approach insisting: "That may work at the neighbourhood butchers, but not in contracts."
But the PM hit back at the demand, which may risk putting a squeeze on NHS supplies and stoke a major row with No 10.
Brussels' health chief Stella Kyriakides told AZ it must begin sending jabs from its two plants in Oxfordshire and Staffordshire to the continent or risk financial and legal penalties.
In an extraordinary outburst, she accused the Anglo-Swedish firm of breaching its contract with the bloc by trying to keep the UK's supply chain separate to that of the rest of Europe.
But Boris hit back at the shameless attempted vaccine grab yesterday, insisting: "We're very confident in our supplies, we're very confident in our contracts, and we're going ahead on that basis.
"I am pleased at the moment we have the fastest rollout of vaccines in Europe and by some way."
BRUSSELS has ordered a spot check on AstraZeneca's vaccine factory in Belgium to check it isn't lying about delays to production as eurocrats' feud with the drugs giant grows ever more bitter.
The EU Commission sent inspectors from the Belgian medicines agency into the plant on Tuesday afternoon amid an increasingly fractious row over Europe's stuttering jabs rollout.
Its extraordinary move was confirmed in a statement by the office of Belgium's health minister Frank Vandenbroucke, which said it was "to make sure that the delivery delay is indeed due to a production problem".
Belgian experts were joined by colleagues from the Netherlands, Italy, and Spain on the raid and will now draw up a report which is set to be released within "a few days".
The shock development comes after a furious German MEP warned that Britain and the EU risk being plunged into a "trade war" by the increasingly bitter feud over vaccine supplies.
Pieter Liese lashed out at AstraZeneca for treating Europeans like "second class citizens" after Brussels demanded the firm start diverting lifesaving jabs from British factories to the continent.
VAX OUT OF ORDER Now EU orders spot check on AstraZeneca’s vaccine factory to check it’s not lying about delays as jabs row boils over
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