Prince Harry, William taking time to regain trust after fallout

Prince Harry and William are reportedly making the efforts in burying the hatchet, hoever experts feel is going to take significant amount of time. 

While the two princes reunited at Prince Philip's funeral for the first time in more than a year, a source said there is still a lot of water under the bridge. 

"I think it's a good start and it was lovely to see but this whole argument runs so deep, I don't think there is any quick fix," a family friend spoke to PEOPLE of their reunion.

According to insiders, there is a lot of work to do before the two are on the same page again.

"Knowing family, it can mend a bit and then can slip back a bit," said a royal insider.

Meanwhile, royal historian Robert Lacey, author of the bestselling biography Battle of Brothers, said, "The procession choreography, in retrospect, was a mistake.

"As we saw, they could have walked side-by-side quite happily after all. What pleased me afterward was that it all seemed so totally natural, and they drifted to each other like the old days," he added.