It is understood the Queen has decided that senior royals attending the service should be in civilian clothing.
The move means that Prince Harry who lost his military titles after stepping down as a senior will not have to be one of the only close family members not in uniform at Saturday's service.
Reports suggested that the Duke of York, who spoke of his father as being "the grandfather of the nation," was considering wearing an admiral's uniform.
Andrew stepped down from royal duties over his friendship with convicted sex offender Jeffrey Epstein in 2019.
He was due to be promoted to Admiral in 2020 to mark his 60th birthday but this did not go ahead following the fallout from his disastrous Newsnight appearance.
The no-uniform rule has been described as "the most eloquent solution to the problem," a military source told The Sun.
The decision is a break with tradition for ceremonial royal funerals and will contrast with the strong military presence which will be on show to honour Philip, who served with distinction in the Second World War.
The news comes as the guest list for the service is expected to be revealed at 1pm on Thursday, April 15.
A maximum of 30 people can attend the funeral because of coronavirus restrictions and social distancing rules.
There would have normally been around 800 members in the congregation inside St George’s Chapel.
The service will be aired from Windsor on major UK channels at 3pm.