The training academy arm of the Busy Bees chain had led the 11-strong provider group, which was set up last year to ensure employers took the lead on developing training standards for the early years workforce.
The group has been working alongside the Institute for Apprenticeships (IFA) panel, which is responsible for approving apprenticeship standards, on developing the Level 3 early years apprenticeship.
But Busy Bees said it has left as it no longer believes the process of setting the early years standards is employer-led.
"We initially wanted to be involved in the process of determining the most appropriate requirements for our Level 3 practitioners so that we could help create a framework that incorporates robust training and effective, meaningful qualifications with agreed standards in place, said Busy Bees training academy chief executive Fay Gibbin.
"We've gained incredible insight into the IFA and have thoroughly enjoyed working with our fellow early years industry experts to this end.
"We are stepping down because we truly believe it should be an employer-led process and unfortunately this has not been the case.
"To reach the outcome we all desire as practitioners who really care about the industry, these decisions should be made by people at the coalface.
"Childcare is, and should be, a highly regulated sector. Therefore, our industry input and knowledge should be vital when agreeing new measurements that ensure future standards work effectively alongside any mandatory regulations.
"I would urge the IFA to listen to the views of employers and give them more involvement in setting the overall standards being discussed."
The National Day Nurseries Association (NDNA) said it seems unlikely the group can continue following the departure of Busy Bees and is calling for a new group, involving early years experts, to be set up to develop the standards.
"We don't see how the current trailblazer group can continue in its current form now that Busy Bees will no longer be a part of it," said NDNA director of training and quality Stella Ziolkowski.
"A new group does need to be set up, but should involve early years experts and key players so that qualifications will be developed to be relevant and exactly what the sector needs.
"At a time when we have a recruitment crisis, the IFA should be listening to the sector. We certainly do not need to return to the debate about maths and English GCSE requirements."
"This is about making a career in early years attractive and exciting to new entrants including apprentices who can learn about children's development and understanding how to support them in their precious early learning experiences. We also need to show how they can progress through to teacher status.
"There must be a clear focus on supporting the age of the children they work with. In order to help close the attainment gap, we know children need to learn numeracy and literacy skills in an age appropriate, play-based way which they can apply in practice. Teaching them trigonometry, for example, would not help them.
"This work needs to be done urgently to help address the existing recruitment and retention crisis.
The trailblazer group was set up in March last year to look at developing early years apprenticeship standards from Level 3 through to degree Level 6.
The Level 3 standards were submitted on 26 September and Gibbin says she hopes these will be published in October.
"We have worked closely with the IFA and DfE to reach a compromise on the assessment methods and we believe this assessment plan will result in a stronger, more skilled workforce," added Gibbin.
The Department for Education declined to comment.