Based on a play called 'Girlfriend', which had a brief West End run in 1970, the most remarkable change made to the film version is that the mysterious partner has been made a West Indian yet that particular revelation is shown not to bother Laurie's parents in the slightest.
There's an awful lot of talk but little is actually said - some of it witty, some of it crass. Michael Hordern looks suitably embarrassed, while Joan Greenwood at 50 has aged considerably, yet, aided by a stylish short haircut, still looks and sounds amazing as only Joan Greenwood could. Clive Francis is the fey son, while 'Straker' with a soft-pitched voice and an afro towers over him as the androgynous Jo. (As with 'Jean Arless' in William Castle's 'Homicidal', the billing of the player was aimed to generate confusion in the mind of the viewer while they both looked strange enough to form a hunch; but Hordern would have been able to tell the difference on the two occasions they kiss.)
It's difficult to tell from the grainy VHS recording which all that is presently available if the sound was originally as muffled or the nighttime exteriors as impenetrable in the original cinema prints; but parts of the film currently sound like the work of Ken Loach. The poor sound operators seem unable to cope with the constant low angles favoured by director Bob Kellett, since the microphone appears several times at the top of the frame. The exaggerated visuals, claustrophobic setting (the action takes place almost entirely in a house where the heating has become stiflingly jammed at full blast), fast pans and unflattering extreme close-ups of Joan Greenwood's perspiring face all look as if Sergio Leone may also have been in attendance.