Just read the EU - Astra Zeneca contract for the Oxford Vaccine.
EU state that their agreement takes precedent over other agreements (no first come first serve) Astra claim that the contract is for Best Reasonable Endeavours to build capacity in EU to deliver the EU order/-

/-2 this does include UK plants. The EU located plants have failed to deliver the order. The U.K. plant is producing well.
The claim that UK has over ordered does not stack up as the EU has ordered 2.3bn doses for its 500m (?) population. Only 300m of this is from Astra./-

/-3 The row comes down to whether the U.K. order should be pushed aside by Astra in order for them to meet the EU contract.

Clause 6.2 states that Astra shall not be liable under the contract for other contracts they have in place interfering with the supply of this agreement./-