(The author is a Reuters Breakingviews columnist. The opinions expressed are their own.)

LONDON - The UK has blown up one of its potential Covid-19 vaccine success stories. French pharmaceutical group Valneva on Monday said the British government had cancelled a deal worth up to 1.4 billion euros, claiming the company is in breach of its supply agreement. Only in February Britain ordered an extra 40 million doses of Valneva’s promising Covid-19 drug, which is close to completing clinical trials. That took the total to 100 million, with an option to buy another 90 million by 2025. The spat follows a much bigger supply battle between the European Union and UK pharma group AstraZeneca.

The loss-making French group’s shares fell over 30% on Monday morning, knocking around 650 million euros off its market value. Yet they are still up more than twofold over the past year. The UK, arguably, looks worse off. Prime Minister Boris Johnson had pumped money into Valneva’s Scottish plant, attracted by the promise of a drug that attacks Covid-19 in multiple ways, potentially making it better at treating mutations. That could have come in handy during the next surge. (By Neil Unmack)

(The author is a Reuters Breakingviews columnist. The opinions expressed are their own.)

(Editing by Peter Thal Larsen and Karen Kwok) ((SIGN UP FOR BREAKINGVIEWS EMAIL ALERTS: http://bit.ly/BVsubscribe))