THE Convict’s Opera is an opera inside an opera.

Performed by the Sydney Theatre Company, led by artistic directors Cate Blanchett and Andrew Upton, and the English Out of Joint, it presents a recital of the Beggar’s Opera on board a convict ship.

The ship sets sail from London to New South Wales, with a motley crew including a forger, an arsonist, a poacher, a conman, a thief and an assortment of political prisoners. On the way, the captain of the ship demands they produce a play.

The play they produce is the Beggars Opera, the wildly popular 18th-century satire by John Gay on opera. Employing a patchwork of hit ballads of the day and ordinary people, it tells the story of a handsome highwayman who attracts two lusty but unscrupulous women and falls victim to the cash-making plans of their fathers.

The Beggar’s Opera performances have a bawdy, pantomime-ish, appeal, complete with cross-dressing, which leads to one of the funniest scenes of the play where Macheath, the highwayman, goes to a tavern filled with ladies of dubious virtue, who variously try to seduce him. In “real” life, Macheath is the black Harry Morton, who turns out to be a slave on the run.

It touches on, but doesn’t really explore, the emotional side of being transported, and the tentative friendships were formed between the convicts, but it’s fleeting.

The real problem lay in trying to engage a 21st-century audience in a typically convoluted plot which meant little to modern audiences. It’s counter-balanced by the superb musicality, zest and joie-de-vivre of the production. The voices, in particular those of Ali McGregor, playing Polly Peachum, and Amelia Cormack, playing Lucy Lockit, were sublime.

The adaptation of songs like I Walk 500 Miles and I Fought the Law . . . was inspired. The cast make the most of an unusual premise and, although testing at times, proved an enjoyable romp.