Holy Deadlock is a 1934 satirical novel by the English author A. P. Herbert, which aimed to highlight the perceived inadequacies and absurdities of contemporary divorce law.

The book took a particularly lenient view of the need for divorces, which it characterised as "a relief from misfortune, not a crime",[1] and demonstrated how the current system created an environment which encouraged the participants to commit perjury and adultery.

In this situation, a popular solution was what was known as "hotel evidence": the man and an uninvolved woman would travel to a seaside resort for a weekend, and go around publicly and ostentatiously as husband and wife.

[4] The Water Gipsies (1930), a story about canal life, was a broad success, which went on to sell a quarter of a million copies and attract comparison to the works of Charles Dickens.

[5] By 1932, he was contemplating a fourth novel to capitalise on this last success; his editor at Punch, E. V. Knox, encouraged him to put aside his theatrical work to focus on writing it.

During a sailing holiday around Brittany with Sir Edward Spears and his wife Mary Borden in late 1932, he filled a notebook with the outline of what was to become Holy Deadlock.

[10] In this case, Herbert was able to let his judge give the "right" answer to the dilemma: he declared that the marriage was dissolved upon the suit of both parties, with no guilt attaching to either, and gave a two-page conclusion in which he decried the law as "illogical, cruel, barbarous and disgusting".

The protagonists are a faultless and honest young couple, with the everyman names of John Adam and Mary Eve, who married impetuously, are now amicably separated, and wish to divorce so that they can remarry; neither has committed adultery nor desired to.

Because of the lack of legal provision, they are compelled to collude to present a fictional cause for divorce; Mary asks Adam to "act like a gentleman" and provide the pretext, as her fiancé, Martin Seal, cannot be named as a co-respondent without risking his job (he works as an announcer for the BBC).

[15] The novel has been noted as a major step in influencing public opinion to support a liberalisation of the divorce laws,[17] though Herbert himself would claim that it merely "helped to create a more favourable attitude".

[22] However, it focused almost entirely on the legal aspects; the broader social issues were not discussed, and the opponents of reform portrayed as "only self-righteous bigots and nice old clergymen incapable of reason".

The lawyers were shown as disinterested and well-informed figures who would tirelessly pursue what they saw as their client's best interests,[23] whilst the protagonists themselves were "sacrificed ... to the sociology, but they do it with a good grace".

[26] Malavika Rajkotia writes that "This novel sparked off the first divorce law reform movement in England, which led to the passing of the Matrimonial Causes Act 1937".

In 1935, he was elected to the House of Commons as an Independent Member of Parliament for Oxford University, and in his maiden speech vowed to introduce a private bill to reform divorce law.