England scrum down with Peel
He also joins Saracens' backroom staff on a permanent basis.
The 39-year-old former Newcastle Falcons prop has coached England's Under-20s since 2013 but will now give up that role, as new England boss Eddie Jones overhauls his backroom ahead of the Six Nations campaign.
"This is a huge opportunity and I am really looking forward to getting stuck in with lots of the guys who I have worked with through the age-group teams, but also when I have gone in and helped Graham Rowntree over the last few seasons," said Peel.
Steve Borthwick (forwards) and Paul Gustard (defence) have already joined Jones's coaching setup after the Australian replaced Stuart Lancaster, whose tenure ended after the World Cup where England became the first host country not to reach the knock-out stages.
The only vacant post remaining is a replacement for backline coach Mike Catt, who was axed along with backroom colleagues Andy Farrell and Rowntree.
"It is a huge honour to go and deliver that for the seniors and joining up with Eddie, Steve Borthwick, Paul Gustard and the rest of the team," he added.
The RFU did not indicate if Peel's role would continue beyond the Six Nations which runs from February 6 to March 19.
Agence France-Presse
