An IDRP may be a one-stage process or a two-stage process
In a one-stage process decisions are taken by the trustees.
In a two-stage process a specified person, such as the pensions manager, takes the first stage decision and there is an appeal to the trustees at a second stage.

Persons with an “interest in the scheme” may bring an IDRP complaint including members, surviving spouses and dependants, prospective members and personal representative of the member.

The IDRP process covers complaints between the trustees and eligible complainants as described above.

Members cannot bring a formal complaint or dispute to the Pensions Ombudsman unless and until they have gone through the scheme’s IDRP.
The Ombudsman will not investigate complaints which are being addressed under the IDRP unless a final decision has been reached or there is no real prospect of a decision being made within a reasonable period and he considers it reasonable to deal with the matter.

The IDRP must include provision for the manner in which an application for the resolution of a pension dispute is made and what information must be given in the application.
The IDRP must also set out the manner in which any decisions required about the IDRP application are to be reached.
There is, therefore, some flexibility for trustees to design the IDRP process in a way that best suits the scheme.
However, there is a statutory requirement for applicants to be provided with information about the Money and Pensions Service when the IDRP application is received.
Applicants must also be given contact details of the Ombudsman when being notified of the IDRP decision.

Trustees must give the postal or electronic address and job title of the person to contact in order to access the IDRP.

Trustees may specify a time limit within which complaints may be made
They must specify a reasonable period for applications to be made by a person who has ceased to have in interest in the scheme.
The Regulator’s Code of Practice states that such a time limit should be set as six months but trustees may agree to accept complaints outside the time limit.

Decisions must be reached and notified to applicants within a reasonable period.
The Regulator’s Code of Practice states that the decision-maker will be expected to determine disputes within four calendar months of receiving the application.
Where the IDPR is a two-stage process the time limit will apply to each stage.
Applicants should be notified of the IDRP decision within 15 working days after the decision has been reached.

The IDPR decision should be recorded in the minutes of the trustee meeting or in a written letter from the Pensions Manager taking the decision.

The Ombudsman has indicated that he believes trustees should give reasons for the decisions taken as part of the IDRP process

Since 2018 the Ombudsman has operated an early resolution service for simpler types of disputes which can be used before the IDRP process.

The Pensions Regulator may impose a fine of up to £5k on individual trustees or £50k for corporate trustees if they fail to implement an IDRP in accordance with legal requirements.