Issue in question
Many applicants hope to improve their applications to Horizon Europe calls for proposals by providing letters of support from various stakeholders. However, such letters are not requested in the vast majority of calls.
Clarification
Letters of support should be submitted with Horizon Europe applications only when specifically requested in the call/topic text (e.g. Host Institution support letter on ERC frontier research grants).
The vast majority of Horizon Europe calls and topics does not require letters of support from stakeholders and expert evaluators are likely to disregard them during evaluation since they do not form part of the official application form.
In addition, submitting such letters further reduces the number of pages available to address the essential evaluation criteria (Excellence, Impact and Implementation), which could be detrimental to the proposal.