Parliament should make an explicit commitment to equal opportunities, a committee of MPs has recommended.

The report, from the standards and privileges committee, said that the MPs' code of conduct should include for the first time a pledge to "uphold the general law against discrimination".

But the independent parliamentary standards commissioner Sir Philip Mawer had advised against the move, saying it would give the impression that equality law was being prioritised above MPs' other legal obligations and could lead to his office being overwhelmed with complaints.

In a letter to the committee, he warned: "Introducing an explicit anti-discrimination provision would open the door to a stream of 'level of service' complaints from disgruntled constituents, alleging that their member's failure to deliver what they want is a reflection of some discriminatory attitude or behaviour."

He said his Scottish opposite number had experienced great difficulty in assessing such 'level of service' complaints.

But the committee concluded that a non-discrimination provision would be of "considerable symbolic importance" and would "reflect current best practice".

The committee also recommended that rules governing the misuse of MPs' expenses should be extended to cover misuse of Commons facilities, such as free computer equipment and free stationery and postage.

This was seen as correcting an anomaly whereby MPs could be censured by the standards commissioner for the improper use of funds, but if they misused Commons facilities - which might be worth far more - they could only be forced to repay the debt.