Musicology experts have given contrasting views at a High Court trial over whether Ed Sheeran’s hit Shape Of You has “significant similarities” or is “distinctively different” from a song he is accused of ripping off.

American forensic musicologist Anthony Ricigliano concluded in a report for a copyright legal row that it was “objectively unlikely” that any similarities between the 2017 track and the song Oh Why by Sami Chokri “result from copying”.

But Christian Siddell, another musicologist, reported that he found melodic similarities were “so numerous and striking that the possibility of independent creation is… highly improbable”.

Mr Sheeran and his co-writers, Snow Patrol’s John McDaid and producer Steven McCutcheon, deny that Shape Of You copies part of the 2015 song by Mr Chokri – a grime artist who performs under the name Sami Switch.

Mr Chokri and his co-writer Ross O’Donoghue claim that a central “Oh I” hook in Mr Sheeran and his co-authors’ track is “strikingly similar” to an “Oh Why” refrain in their own composition.

Both musicology experts gave evidence on their analysis of the songs at an ongoing trial in London on Wednesday.

In a joint written statement, they agreed that “when heard in the context of their respective works, the words ‘Oh why’ and ‘Oh I’ may be phonetically indistinguishable from each other to the casual listener”.

They also agreed that neither of them had found “the same combination of either the ‘Oh Why’ phrase – combined phonetic sound plus pitch and rhythm – nor the ‘Oh I’ phrase – combined phonetic sound plus pitch and rhythm – in any other compositions”.

Lawyers for Mr Chokri and Mr O’Donoghue allege that when the two songs’ melodies are transposed into the same key “the progression of notes is the same”.

They also claim the rhythm of the tracks’ melodies are “almost identical”, their use of instrumentation “creates a strikingly similar sound and texture” and the vowel sounds in the chanted tune “further enhances the similarity”.

Mr Ricigliano, who was instructed by the Shape Of You co-writers’ lawyers but told the court he was “completely impartial”, said in a report that he considered the extent of the alleged similarities between the two songs to be “overstated”.

He wrote that “the overall design and musical development of the melodic, harmonic and lyrical content in the relevant phrase in Shape Of You are distinctively different from that utilised in Oh Why”.

Mr Ricigliano added: “Such similarities as there are, when placed in context, in my view lack significance in relation to the allegation of copying from Oh Why.

“They are commonplace forms of expression, both in terms of use by other writers and by Mr Sheeran himself.

“My view is therefore that it is objectively unlikely that any similarities result from copying.”

In court, Andrew Sutcliffe QC, representing Mr Chokri and Mr O’Donoghue, asked him: “You accept, don’t you Mr Ricigliano, that despite all your research you have not found any examples in any corner of the earth over the past 200 years which sound phonetically the same as the chorus in Oh Why and the post chorus in Shape Of You.”

“That’s correct,” Mr Ricigliano said.

“Do you not find this extraordinary?” Mr Sutcliffe asked, with the expert replying: “No”.

The barrister described the two song phrases as appearing “within months of each other” and suggested they sound “almost the same”.

“I would disagree with the characterisation,” Mr Ricigliano said, adding that the two are “coincidentally similar” and have “distinctive differences”.

Mr Sheeran has argued in his written evidence that his song’s Oh I phrase uses “a basic minor pentatonic pattern” which is “entirely commonplace”.

In court, Mr Siddell, who was instructed by Mr Chokri and Mr O’Donoghue’s lawyers but outlined his own professional opinion in his report, said he felt there had been “over emphasis” in relation to references to the minor pentatonic scale in the case, adding: “The Oh I and Oh Why phrases are melodies not scales.”

In his own report he concluded that there were “striking and substantial similarities between certain aspects of the lead vocal melody of Oh Why and Shape Of You”.

He said the two melodies were “nearly identical in respect of their rhythm and pitch”, the phonetic sounds of the vocal lines were “musically indistinguishable to the ear” and other compositional similarities included the use of “phrase repetition” and “the musical dynamics”.

Mr Siddell said that similarities between the two works were “unlikely to be the consequence of coincidence”.

“From a solely musical perspective, I find the melodic similarities to be so numerous and striking that the possibility of independent creation is in my view highly improbable,” he said.

He added: “Had I been consulted in a ‘copyright compliance’ capacity as to whether a licence should be sought from the writers of Oh Why, my guidance would have been, in summary, that either the melodic phrase should be omitted and replaced with original new material or a licence should be obtained.”