Here's from blacktieguide, with a quote from Manton even:
The cardinal rules for alternative jackets is that they are appropriate only for less formal occasions, such as a private party at home or at a private club, and that all other aspects of one’s ensemble comply with the rules for proper black tie. Even then, advises menswear author Nicholas Antongiavanni, they “should be approached with caution for they do not command universal respect.”
As the inspiration for the original dinner jacket, the smoking jacket remains a popular alternative to the traditional black-tie coat. Although fashioned in many different styles it is always constructed of colored velvet in dark hues usually of green, violet, burgundy or blue. The most authentic types of smoking jacket can be either double-breasted or single-breasted and have frog closures in place of buttons as well as a self-faced shawl collar. Classic variations popular in the 1930s were velvet hybrids that featured standard buttons and had self-faced peaked lapels on the double-breasted models or silk-covered shawl collars and cuffs on the single-breasteds.
More contemporary iterations are simply tuxedo jackets in every detail except for the velvet fabric. English haberdashers often include these designs in the smoking jacket category while North Americans are more likely to refer to them velvet dinner jackets. The American moniker may better describe the garment's appearance but the British terminology reflects its suitability for informal lounging rather than formal dining. These pseudo dinner jackets are discussed further on in Contemporary Jackets.