The former home secretary, Jacqui Smith, has been ordered to apologise to the House of Commons after an investigation concluded she had broken the rules on second home expenses.

Smith, the MP for Redditch, became the first cabinet minister to be embroiled in the scandal after she was revealed to have registered her sister's London house as her "main home". This allowed her to claim expenses on her constituency home in Worcestershire where her husband and children live.

The Commons Standards and Privileges Committee said Smith had "clearly" breached the rules by claiming her sister's house as her main home.

The Standards Commissioner, John Lyon, said: "The gravitational pull in terms of family and property is, on the basis of all the evidence I have seen, Redditch and not London."

The committee said that it was a "significant mitigating circumstance" that Smith had sought and acted in accordance with advice from the House of Commons authorities in 2007.

But it concluded: "Ms Smith clearly breached the rules of the House by wrongly designating her main home from 2004 to 2009. We recommend that Ms Smith apologise to the House by means of a personal statement."

In a statement, Smith said: "I am disappointed that this process has not led to a fairer set of conclusions, based on objective and consistent application of the rules as they were at the time."

She said the report, "appears to be heavily influenced by subjective judgements about my personal circumstances."

Smith was further embarrassed during the scandal when it was revealed that she had claimed for pay-per-view films including two pornographic movies watched by her husband. The committee upheld the complaint over the films but accepted that Smith had paid back "a sum in excess" of the amount she claimed.