The MU has said the live band, led by Dave Arch, has been limited to its rhythm section, made up of seven musicians, while the rest of the band, which it says varies in number, are pre-recorded in a studio during a three-hour session. Figures do not include the singers who continue to perform live on the show. The union said it did not “accept” that Strictly “needs to cut corners in this way”, with one musician accusing the BBC of using “silhouetted areas that could be assumed to be positions of musicians present” to hide the fact the band was smaller.

It said the BBC has offered a compromise of bringing back the full band for four episodes, however the union wants it to return for the full series. The corporation said it had decided to cut the band’s brass section in order to “ensure the best value for money for audiences”. The last time Strictly used its full band for the whole series was 2019.

Geoff Ellerby, the MU’s national organiser for recording and broadcasting, said: “Due to the Covid-19 crisis, some band members’ performances were pre-recorded as a necessary safety precaution, with a significantly reduced live band performing along to these backing tracks. “We worked hard with broadcasters and studios in mitigating the risks to get musicians working under new restrictions, and although we were agreed that following these temporary measures we would work towards normality as soon as possible, Strictly is refusing to re-instate the full live .