Boris Johnson has insisted HMS Defender was “entirely right” to voyage through the disputed waters around Crimea as Russia threatened to retaliate if there was a repeat of the incident.

Moscow claimed that warning shots were fired by Russian vessels at the destroyer as it passed through the contested part of the Black Sea on Wednesday – an assertion dismissed by the UK Government, which said only that a routine “gunnery exercise” took place.

The Prime Minister said the route was “wholly appropriate” and the destroyer was part of an international Carrier Strike Group that was “sticking up for our values”.

Speaking to reporters at a barracks in Aldershot, Mr Johnson sidestepped a question on whether he had personally authorised HMS Defender’s voyage.

“These are a matter for the MoD (Ministry of Defence) but if you want my view I think it was wholly appropriate to use international waters, and by the way the important point is that we don’t recognise the Russian annexation of Crimea, this is part of a sovereign Ukrainian territory, it was entirely right that we should indicate the law and pursue freedom of navigation in the way that we did, take the shortest route between two points, and that’s what we did.”

The Prime Minister’s official spokesman also refused to be drawn on whether Mr Johnson personally authorised the mission, telling reporters: “I’m not going to get into operational military decision-making.”

Dramatic eyewitness accounts revealed the Type 45 destroyer was buzzed by Russian military jets and the sound of naval gunfire could be heard as it sailed from Odessa in Ukraine to Georgia on Wednesday.

The MoD denied claims from Moscow that shots were fired by a Russian patrol boat towards HMS Defender, and that a warplane dropped four high-explosive fragmentation bombs in its path during its passage through the Black Sea.

Asked whether the UK was telling “barefaced lies” over the incident, as alleged by Russian foreign ministry spokeswoman Maria Zakharova, Mr Johnson said: “Well, they’re the bear.

“That’s not my information and my understanding is that the Carrier Strike Group proceeded in the way you would expect through international waters and in accordance with the law.”

Defence Secretary Ben Wallace gave further details of the incident in a written statement to MPs.

He said that 10 minutes after entering the traffic separation scheme shipping lane inside Ukrainian territorial waters, a Russian coastguard vessel “warned that Russian units would shortly commence a live fire gunnery exercise”.

Mr Wallace said:

– HMS Defender was overflown by Russian combat aircraft at varying heights, the lowest of which was approximately 500 feet, with some of the manoeuvres “neither safe nor professional”.

– On one occasion the destroyer had to “avoid a hazard presented by a Russian coastguard vessel” before re-assuming her intended course.

– HMS Defender responded by VHF radio to the Russian units on several occasions “and was, at all times, courteous and professional”.

“The Royal Navy will always uphold international law and will not accept unlawful interference with innocent passage,” Mr Wallace told MPs.

HMS Defender is part of the UK Carrier Strike Group currently heading to the Indo-Pacific region.

However, it was announced earlier this month that it would be temporarily breaking away from the group to carry out its “own set of missions” in the Black Sea.

Russia’s deputy foreign minister, Sergei Ryabkov, said “the inviolability of the Russian borders is an absolute imperative”, adding that it will be protected “by all means, diplomatic, political and military if needed”.

Asked what Russia would do if a similar incident happened again, he said: “We may appeal to reason and demand to respect international law.

“If it doesn’t help, we may drop bombs and not just in the path but right on target if colleagues don’t get it otherwise.”

Cabinet minister George Eustice told Sky News that the UK would be prepared to send another vessel on the same route.

Asked if the Government would do it again, he said “of course, yes”, adding: “We never accepted the annexation of Crimea, these were Ukrainian territorial waters.”

The move has put a further strain on already difficult diplomatic relations between London and Moscow.

British ambassador Deborah Bronnert was summoned to the ministry of foreign affairs in Moscow after Russia accused the Type 45 destroyer of straying into its territorial waters.

Former Royal Navy chief Admiral Lord West accused Russian president Vladimir Putin of “playing to the home audience”.

The former first sea lord told LBC: “The bottom line is Putin is an expert at disinformation and his actions are very reckless, and we’ve seen that now for three or four years.”

The latest flare-up comes amid months of tension between Moscow and the West following a build-up earlier this year of Russian forces on the border with Ukraine.

The Kremlin, which annexed Crimea in 2014, has been riled by the movement of Nato warships in the Black Sea seen as offering support to Ukraine.

To underline Moscow’s point, the Russian embassy chose a picture of the Crimea as its daily post of a “Russian” landscape.