Snow Patrol's Johnny McDaid has described the idea of stealing other people's work as "abhorrent", during the copyright trial over a song he wrote with Ed Sheeran.
Sheeran, McDaid and co-writer Steve Mac have been accused of taking "particular lines and phrases" for the song Shape Of You from a track called Oh Why, by an artist called Sami Switch.
In written evidence, McDaid said he could not recall ever hearing Oh Why "in any way" and was unaware of Sami Switch before the legal case began.
The musician is more well-known to the public as Johnny McDaid, but in the court papers he is named as John.
He has written hits for Pink, BTS, Alicia Keys and Rag'n'Bone Man, added that he would never take credit for another writer's work.
"I have been a professional songwriter for many years and have achieved substantial success," he wrote.
"I do not need or want to, nor would I ever, plagiarise other people's work. The idea is abhorrent to me."
Oh Why was written by Ross O'Donoghue and Sami Switch, under his real name Sami Chokri, in 2015.
The pair claim that Sheeran stole their hook for the post-chorus of Shape Of You, changing the lyrics to "oh I, oh I, oh I".
In court on Tuesday, Sheeran denied the accusation; and sang elements of Nina Simone's Feeling Good to illustrate how the melody was a common part of pop music.
McDaid, who is godfather to Sheeran's daughter and the partner of Friends star Courteney Cox, also asserted that there was "nothing original" about the melody.
"[It] uses sequential notes from the pentatonic scale," he said in his written statement. "It is a very common melodic structure, in my experience."
He recalled the creation of Shape Of You as a "frenetic, rapid process", with all three writers suggesting lyrics and melodies.
"The words 'shape of you' came from me," he added. "It is a phrase used in Derry, where I come from.
"I am sensitive to objectification and I was not keen on 'in love with your body' so I suggested the more abstract 'shape of you', although both appear in the song in its finished form."
He said he could not remember who came up with the "oh I" section, describing it as "filler" to "make the song flow".
During the opening days of the trial, the court heard that Sheeran and McDaid had settled a previous plagiarism case over their song Photograph.
They also added the writers of TLC's No Scrubs to the credits of Shape Of You over similarities between those two songs.
McDaid took issue with the suggestion that these settlements suggested "I was in the habit of consciously or sub-consciously appropriating the skill and labour of other songwriters during my songwriting and recording sessions".
"I wholeheartedly disagree with this implication," he said in his witness statement. "It is simply not true and I feel that is a very serious thing to suggest about me and how I work."
Culture of copyright claims
In court on Wednesday, the songwriter was questioned further about the Photograph case, in which he and Sheeran were accused of copying a song called Amazing by X Factor winner Matt Cardle.
McDaid emphasised he only paid a "proportion" of the £4m settlement, which he said was reached under legal advice.
"It was not settled because we believed that we had copied Amazing in any way," he said in his written evidence.
At the time, he added, there was "a culture" of US copyright trials which "really wasn't going favourably for songwriters at all" - presumably a reference to the controversial Blurred Lines case, where Robin Thicke and Pharrell Williams were found guilty of copying the "feel" of Marvin Gaye's Got To Give It Up, rather than directly plagiarising musical phrases or lyrics.
Shape Of You was released in January 2017 as one of two lead singles from Ed Sheeran's third album, Divide.
It went to number one around the world and remains the most-streamed track of all time on Spotify, with more than 3 billion plays.
The dispute over the song dates to May 2018, when Sheeran and his co-authors launched legal proceedings, asking the High Court to declare they had not infringed Chokri and O'Donoghue's copyright.
Several months later, Chokri and O'Donoghue issued their own claim for "copyright infringement, damages and an account of profits in relation to the alleged infringement".
The case is expected to last three weeks, with McDaid returning to the witness stand on Thursday.