The two men became embroiled in a tit-for-tat paddock row during the Chinese Grand Prix this weekend which appears to be heading for the High Court.

The disagreement surrounds aerodynamicist Dan Fallows, who opted to quit Red Bull in September last year and join McLaren.

After being placed on a period of gardening leave, Fallows was due to commence work with McLaren in early March - only to be rehired by Red Bull where he has been working for the last two weeks.

That prompted McLaren group chief executive Dennis to launch a tirade against Red Bull, describing the situation as "completely unacceptable."

Dennis made clear he had been left with no alternative but to pursue a High Court action against Red Bull, where "very serious questions as to that team's integrity and sense of fair play" would be asked.

On the grid minutes before the start of Sunday's race, Dennis and Horner were caught engaged in conversation.

Asked as to the nature of their talks, Horner jokingly replied: "He just said 'Happy Easter'."

Pressed on the matter, Horner added: "The situation with Dan is very clear - Dan decided he would leave Red Bull for reasons of his own.

"With the changes that happened at McLaren he decided he didn't want to join.

"He then approached us to see if there was a situation still open, so it was 100 per cent his choice.

"Taking this to the High Court, getting lawyers involved and so on, if that's the way McLaren want to act then that's what will have to be done."