Politician on maternity leave accuses British government of cheating her

Member of Parliament Jo Swinson makes a speech during the second day of the Liberal Democrats autumn conference at the Bournemouth International Center.

London (CNN)A British lawmaker on maternity leave has accused Theresa May's government of "cheating" after it broke an agreement that cancels out the votes of politicians who are unavoidably absent from parliament.

Jo Swinson, the deputy leader of the Liberal Democrat party, believed she did not need to be present for a key Brexit vote on Tuesday because a member of May's Conservative party had agreed not to cast an opposing ballot.
But the Conservative MP in question, party chairman Brandon Lewis, voted in support of the government, contributing to a narrow, six-vote win for May's beleaguered administration.
    Swinson said Lewis had broken a longstanding arrangement that allows British lawmakers who are absent from parliament to be "paired" with opposing MPs who agree not to vote, thereby balancing out the tally.
    Wrtining on Twitter Swinson described the move as "desperate stuff" and said the government "broke an agreement" that benefited pregnant women and new mothers in parliament.
    "Just how low will your govt stoop @theresa_may?" she wrote.
    "This is calculated, deliberate breaking of trust by govt whips... to win at all costs," she added. "There's a word for it -- cheating."
    Lewis apologized on Twitter, describing the incident as "an honest mistake" made by party administrators "in fast-moving circumstances."
    "I know how important the pair is to everyone, especially new parents, and I apologise," he wrote.
    David Lidington, a senior meber of May's cabinet, also apologized to Swinson Wednesday morning, telling BBC Radio 4's Today program that it was a "genuine mess-up" that "clearly should not have happened."
    Conservative Party Chairman Brandon Lewis arrives for a cabinet meeting in Downing Street on July 10.
    Swinson rejected Lewis' explanation, arguing that it was "not credible" that the MP "forgot" he was paired for the day's two key votes, having already abstained in several others earlier Tuesday.
    The Scottish MP, who announced the birth of her son Gabriel on July 1, used the incident to highlight the problem of discrimination faced by pregnant women and new mo