What is a Senior Independent Director

Most boards are built around two leadership roles: the chair, who leads the board, and the chief executive, who leads the business. The senior independent director is the third leadership role on a well-governed board. It exists to deal with the situations the other two cannot. These are concerns about the chair, a breakdown between chair and chief executive, or a shareholder who has not been heard through the usual channels.

This page is our definitional overview of the role. For how SIDs actually spend their time and handle difficult moments, see our guide to the senior independent director in practice. For the process of choosing one, see how to appoint a senior independent director. For FCA and PRA-regulated firms, where the role can be a regulated function, see our page on SMF14 senior independent director.

What Is a Senior Independent Director?

A senior independent director is one of the board’s independent non-executive directors who has been formally appointed to an additional leadership role. They remain a non-executive director, with the same legal duties as every other director under the Companies Act 2006. “Senior independent director” is not a separate legal office. It is a governance role, created by corporate governance codes and defined by the board.

The word “senior” does not mean the SID outranks the other non-executives in day-to-day board business. Every director has an equal vote and the same responsibility. The seniority lies in the specific functions the SID performs, which become important at exactly the moments when ordinary governance channels are not working.

What the UK Corporate Governance Code Says

For companies that apply the UK Corporate Governance Code, the role is set out in Provision 12 of the 2024 Code:

The board should appoint one of the independent non-executive directors to be the senior independent director to provide a sounding board for the chair and serve as an intermediary for the other directors and shareholders. Led by the senior independent director, the non-executive directors should meet without the chair present at least annually to appraise the chair’s performance, and on other occasions as necessary.

Three other parts of the Code connect directly to the role:

• Provision 14 says the responsibilities of the chair, chief executive, senior independent director, board and committees should be clear, set out in writing, agreed by the board and made publicly available. Most listed companies publish a written statement of the SID’s role on their website.
• Provision 17 says the chair of the board should not chair the nomination committee when it is dealing with the appointment of their own successor. In practice, the SID often leads that process.
• Provision 3 expects the chair to seek regular engagement with major shareholders. The SID provides an alternative route where shareholders’ concerns have not been resolved through the chair or executives.

The Code applies on a “comply or explain” basis. Our guide to how the UK Corporate Governance Code impacts non-executive directors explains how that works.

The Four Core Functions of the SID

1. Sounding board for the chair

The SID is the chair’s trusted confidant on the board: someone the chair can test ideas with, discuss difficult board dynamics with, and ask for candid feedback. This works only if the SID is willing to give honest views, including uncomfortable ones. A SID who simply reassures the chair is not doing the job.

2. Intermediary for the other directors

Non-executive directors sometimes have concerns they find difficult to raise directly with the chair. This might be about how the chair runs meetings, the chair’s relationship with the chief executive, or the chair’s own conduct. The SID gives them a route to raise those concerns, and helps the board work through them constructively. Our guide to managing disagreements between NEDs and executives shows how this fits into the wider escalation path.

3. Intermediary for shareholders

Where a shareholder has concerns that have not been resolved through the chair or the executive team, or where the concern is about the chair, the SID is the board member they can contact. In listed companies this is used most by institutional investors. The SID’s availability is often stated in the annual report or on the company’s website.

4. Leading the appraisal of the chair

The Code expects the non-executive directors, led by the SID, to meet without the chair at least once a year to appraise the chair’s performance. The SID gathers views from fellow NEDs and usually from the executive directors, gives feedback to the chair, and makes sure any issues are followed up. This is one of the most important parts of the role, because no one else on the board is in a position to do it. For more on how individual director performance is reviewed, see how NED performance is measured, and for the whole-board process see how board effectiveness reviews work.

Other Responsibilities SIDs Commonly Take On

Beyond the four core functions, boards often give the SID additional responsibilities in the written statement of the role. These commonly include:

• Chair succession. Leading the search for a new chair, or chairing the nomination committee when it deals with the chair’s successor. Our guide to succession planning for NEDs covers planning ahead for this.
• Stepping in during a crisis. Providing continuity and leadership if the chair is incapacitated, conflicted or leaves unexpectedly, until an interim or permanent arrangement is in place. See our page on interim chair appointments.
• Chair–CEO relationship. Helping to resolve tension between the chair and chief executive, or between the board and a major shareholder.
• Whistleblowing and serious concerns. Acting as a contact point for serious concerns, especially where they involve the chair or chief executive.

Who Can Be the SID?

Under the Code, the SID must be one of the independent non-executive directors, meaning a NED the board considers independent under the circumstances set out in Provision 10. A non-independent director, such as an investor-appointed director or a former executive, would not meet the Code’s expectation. Our guide to the difference between an independent and a non-executive director explains the independence test.

Beyond independence, boards typically look for:

• board experience and standing, so the chair, executives and shareholders take the SID seriously;
• independence of mind and the confidence to deliver difficult messages to the chair;
• judgement and discretion in handling confidential concerns;
• good relationships across the board, without being too close to the chair; and
• enough time to handle a crisis on top of their normal commitments.

The SID can also chair a board committee, and often does, although boards should check whether combining roles leaves enough time and avoids concentrating too much influence in one person.

SID vs Chair vs Deputy Chair

The three roles are often confused. They are different:

• The chair leads the board, sets its agenda, makes sure directors get the information they need and is the main link with shareholders. Our guide to what a company chairman does explains the role.
• The senior independent director supports and, where necessary, challenges the chair, acts as an intermediary for directors and shareholders, and leads the chair’s appraisal. The role exists partly to provide a check on the chair.
• A deputy chair or vice chair, where a company has one, stands in for the chair when needed. Some companies combine the deputy chair and SID roles. Others keep them separate, because a deputy who is being groomed as the chair’s successor may not be well placed to appraise or challenge the chair.

The relationship between chair and chief executive is a separate question. Our guide to CEO vs chairman covers where power sits between them.

Do Private Companies Need a SID?

There is no legal requirement for any company to appoint a senior independent director, and the Code applies only to companies that report against it. Many private companies, PE-backed businesses and family companies nonetheless find the role useful, especially where:

• the chair is a founder, major shareholder or former chief executive, and other directors need a safe route to raise concerns about them;
• there are several independent non-executives and the board wants a structured way to appraise the chair;
• the company is preparing for a listing and wants Code-style governance in place early; or
• there are minority shareholders, lenders or investors who would value a named independent contact.

On a small board with only one or two non-executives, a formal SID role may add little. A clear understanding of who leads the chair’s appraisal and who directors can go to with concerns may be enough. Our guides to building a board for a family business and board structure, composition and independence discuss how roles fit together on smaller boards.

The SID in Regulated Financial Services

In larger FCA and PRA-regulated firms, the senior independent director role can be a Senior Management Function under the Senior Managers and Certification Regime, designated SMF14. That means the individual needs regulatory approval before taking up the role, is subject to the conduct rules and carries personal accountability. Which firms must have an SMF14 depends on how they are regulated, so firms should check the current rules. See our SMF14 senior independent director page and our FCA-regulated board governance hub.

Frequently Asked Questions

What does SID stand for?
SID stands for senior independent director. It is an independent non-executive director appointed to an additional role as a sounding board for the chair, an intermediary for other directors and shareholders, and the leader of the chair’s annual appraisal.

Is the SID a legal role?
No. It is a governance role set out in the UK Corporate Governance Code and defined by the board. The SID has the same legal duties as every other director under the Companies Act 2006, although in some regulated firms the role is also a Senior Management Function requiring FCA or PRA approval.

Does the SID have to be independent?
Under the UK Corporate Governance Code, yes. Provision 12 says the board should appoint one of the independent non-executive directors as SID. Companies that do not apply the Code can set their own approach, but appointing an independent director is good practice.

Who appraises the chair?
The Code expects the non-executive directors, led by the SID, to meet without the chair present at least annually to appraise the chair’s performance. The SID usually also gathers the views of the executive directors and feeds back to the chair.

Can the SID become the next chair?
It is possible, but boards should think carefully. A SID who is a likely successor may find it harder to appraise or challenge the current chair objectively, and may need to step back from leading the succession process if they are a candidate.

Is the SID paid more than other NEDs?
Commonly, yes. Many companies pay the SID a supplement on top of the base NED fee to reflect the extra responsibility and time. Our NED salary guide covers how fees and supplements are set.