Prince Philip will be laid to rest in a coffin which was made alongside one for the Queen, it has been reported.
The 99-year-old Duke of Edinburgh died on Friday and his final resting place will be in St George's Chapel in Windsor.
No one knows when the Duke's coffin was made as the company inherited them in 1991, The Sun reports.
Buckingham Palace had looked at a number of choices for coffin which includes a £900 casket made of wool.
AW Hainsworth, which makes woollen coffins, has previously made the military uniforms worn by Prince William and Harry at their weddings.
Another option is a coffin with a lead lining to keep moisture out and preserve the body for longer.
The Duke's coffin will be carried from Windsor Castle in an open-top electric Land Rover Defender 130 Gun Bus he helped create and also reportedly modified.
Saturday's 3pm service will be held against the backdrop of a pandemic and will also bring senior royals together for the first time in about a year.
It is said the Duke didn't want a fuss and he will get his final wish due to England's lockdown rules.
Only 30 guests, who must wear face masks, can attend the televised funeral which will start when his coffin arrives.
Prince William and Harry and other senior royals will follow the Land Rover on foot.
But the coffin is unlikely to be shown at the funeral on Saturday as it will be draped in the Duke's personal standard.
Philip will one day be buried with the Queen in the memorial chapel in Frogmore Gardens but until then his body will lie in the Royal Vault.
The Queen has given final approval to the funeral plans, codenamed Forth Bridge, and eight days of national mourning, which will end on Saturday.
Details of the service and guest list will be released by Buckingham Palace on Thursday.
A spokesperson said the funeral matches the personal wishes of Philip.
They said: "This event will be much reduced in scale with no public access. In line with Government guidelines and public health measures, there will be no public processions and the Duke's funeral will take place entirely within the grounds of Windsor Castle,' he said.
"The plans have been given final approval by the Queen and reflect appropriately Government advice. Despite these necessary changes, they still very much reflect the personal wishes of the Duke.
"Although the ceremonial arrangements are reduced, the occasion will still celebrate and recognise the Duke's life and his more than 70 years of service to the Queen, the UK and the Commonwealth."