Labour MP Frank Field is probing The Pensions Regulator and trustees of the Barclays defined benefit (DB) pension on changes that will see the scheme become part of the split-off investment banking business.
According to new regulations brought in to strengthen the financial system following the financial crisis, banks will need to ring-fence their retail business, separating it from more riskier activities, such as investment banking.
Barclays will satisfy this requirement by setting up a new ring-fenced bank, subject to approval, in April 2018.
However, Barclays Bank UK Retirement Fund (UKRF), the banking giant's final salary scheme, will be moved to the investment bank after 2025.
Due to concerns about the future of pension fund members pension pots, Mr Field, chairman of the Work and Pensions select committee, will be writing to The Pensions Regulator (TPR) and the scheme trustees, he told FTAdviser.
Baroness Ros Altmann, former pensions minister, is also concerned about this change.
She said: "I hope that trustees and the regulator are looking into this carefully, and that the funding of its massive liabilities will not be compromised.
"It may be fine, but members and other employers who themselves are supporting the Pensions Protection Fund [PPF] insurance programme for all final salary-type schemes, need some reassurance that the scheme's backing has been adequately considered."
With liabilities of £42.5bn and assets of £34.6bn, the scheme has a deficit of £7.9bn, according to its triennial actuarial valuation conducted in September 2016.
A deficit recovery plan, with annual payments until 2026, has been agreed, according to the Barclays ring-fencing transfer scheme report, conducted by Grant Thorton UK.
A spokesperson for the The Pensions Regulator told FTAdviser that the regulator is aware of the plan, and that it has discussed it with the bank and the scheme trustees.
He said: "Barclays has not made a clearance application nor have we approved the bank's plans. We continue to work closely with the trustees and assess the impact on the scheme.
"As clearance has not been provided, all of our powers (including our anti-avoidance powers) remain available to us. We would not hesitate to use our powers if necessary."
Grant Thorton's report says that the bank and the scheme trustees consider that there is no adverse effect to the pension scheme due to the ring-fencing changes, and that for this reason the bank will not be submitting a clearance application at this time.
A clearance statement from The Pensions Regulator gives assurance that, based on the information provided, the regulator will not use its anti-avoidance powers to issue to either contribution notices or financial support directions in relation to a defined benefit scheme and a particular event.
According to Nathan Long, senior pension analyst at Hargreaves Lansdown, the change in the supporting company of the defined benefit scheme is "important because the promises are only as strong as the employer that is backing up the pension".
He said: "There is no reason to suggest that the investment bank will get into difficulties, and even if this were the case, the backstop of the PPF will ensure that most members will receive the lion share of their pension entitlement.