Boris Johnson went out of his way this week not to blame Delhi for the later-than-expected arrival of 5m doses of the Oxford vaccine from India, which is contributing to a significant dip in supplies in April.

“No, no, no,” he said, when asked by a reporter whether Delhi had blocked the export of the vaccines, as the country battles a resurgence in Covid cases.

Instead, he praised the Serum Institute of India, which is manufacturing the Oxford/AstraZeneca vaccine, and stressed the importance of a global approach.

Johnson’s remarks were in stark contrast to the robust response from the foreign secretary, Dominic Raab, when the president of the European commission, Ursula Von der Leyen, threatened to slap an export ban on vaccines due to leave the EU.

“If the situation does not change, we will have to reflect on how to make exports to vaccine-producing countries dependent on their level of openness,” Von der Leyen said earlier this week, in remarks widely interpreted as aimed at the UK.

The EU’s management of its vaccination programme has at times appeared chaotic, with several member states temporarily halting delivery of the AstraZeneca jab over safety concerns in recent days, at the same time as the commission was bemoaning a shortage of supplies.

Leaked figures earlier this week showed that 34m doses of vaccines had been exported from EU manufacturing facilities, more than 9m of those to the UK. The UK insists these have been contracted and paid for, mainly from Pfizer.

Raab hit back at Von der Leyen’s comments, saying: “Frankly, I’m surprised we’re having this conversation. It is normally what the UK and EU team up with to reject when other countries with less democratic views than our own engage in that kind of brinkmanship.”

The row with the EU appears to have been heightened by the Brexit situation, with many of the same personnel involved.

But government insiders say the tough reaction to Von der Leyen’s statement also reflects genuine concern in Whitehall at what moves the EU might now make, with cases rising sharply in some countries and vaccination programmes faltering.

“There’s been a huge amount of alarm, because we’re aware that they’re in a very, very difficult place, and there’s a risk of making very poor decisions that harm the bilateral relationship for years or even decades to come,” said one official.

Ministers are acutely conscious that supply chains for the vaccines and their components are global, and a slew of tit-for-tat export restrictions would have disastrous consequences. It is for that reason Johnson told the House of Commons: “We oppose vaccine nationalism in all its forms” – despite previously hailing various aspects of the the UK’s pandemic response as “world-beating”.

The EU situation is different to the Indian delay, government insiders say. They point out that 5m doses have already been delivered from India, and the arrival of the rest is a matter of timing, with discussions continuing. “There’s a calm,” said one Whitehall official involved. By contrast, the EU appeared to be suggesting tearing up commercial contracts.

Emollience towards Delhi also suits the “tilt” towards the Indo-Pacific region outlined in Johnson’s strategic and defence review this week, and which will be underlined when the prime minister visits India later in the spring.

He won’t want to fall out too badly with the EU either, however. Weighing on the prime minister’s mind will be the fact that he is due to host leaders of the G7 nations in Cornwall in June (travel restrictions allowing), and will not want to do so against the backdrop of a vicious diplomatic spat.

But this week’s events have only strengthened the view in government that the safest way to secure supplies for future vaccine rounds – which Matt Hancock has said may have to begin with a booster shot in the autumn – is to bolster the UK’s domestic capacity still further. Meanwhile, ministers will be watching developments in EU capitals very closely.