A BBC editor joked that Sir Cliff Richard would soon be playing Jailhouse Rock, after learning police were investigating an allegation of historic sexual assault against the singer.

Declan Wilson, who at the time ran the BBC’s north of England bureau, made the comment to a colleague while discussing the broadcaster’s plan to cover a police raid on the veteran singer’s house in August 2014.

“Soon to play Jailhouse Rock, or was that Elvis?”, wrote Wilson in an email to BBCUK news editor Gary Smith.

Wilson told the high court that the email was “just a bit of a joke between colleagues who knew each other very well” and said in no way did it “set a tone for our coverage of the story”.

In a witness statement he described how he first told Smith about the news that Richard was under investigation through an email entitled: “SIT DOWN WHEN YOU READ THIS.”

Wilson also defended BBC journalist Dan Johnson, who received the initial tip that led to the story. The news editor explained that the reporter was initially praised for breaking the news that South Yorkshire police were investigating a claim that a young man had been sexually assaulted by Richard in the mid-1980s: “This lad has gone from hero to zero very quickly.”

Richard strongly denied the claim an assault had taken place following an appearance by the evangelical preacher Billy Graham in Sheffield and no charges were brought.

The singer is suing the BBC and seeking substantial damages, arguing that the broadcaster invaded his privacy with its coverage of the investigation, which included flying a helicopter over his Berkshire home to film police officers inside.

Earlier in the day, Johnson admitted emailing his manager to discuss getting in touch with Graham to ask “if it was more than the hand of God doing the touching”.

The reporter told the court that his relationship with South Yorkshire police broke down in the aftermath of the raid when a BBC colleague speculated on how the story had been obtained.

Johnson said he did his best to stop home affairs correspondent Danny Shaw from writing a piece for the BBC website, which suggested the story had been a “deliberate attempt by police to ensure maximum coverage” for the investigation, an accusation that Johnson said angered South Yorkshire police.

“I thought the Danny Shaw gave, in part, a misleading representation of what had actually happened,” Johnson told the court, confirming that he later attempted to have the piece by his colleague edited from the BBC website.

“I thought by having that amended, Danny Shaw’s article would be more accurate and South Yorkshire police would possibly be more happy working with me.”

Johnson, who previously told the court he guessed Richard’s name after a conversation with an anonymous source, said he was concerned about how much information Shaw wanted about the story and and would “rather it wasn’t written in the first place”.

“He wanted to understand more about the source of the story and how things had played out with South Yorkshire police,” he added. “Things I wasn’t comfortable explaining because of the source protection issues.”