Countdown host Anne Robinson has been criticised for taking 'nanna naps' while recording the daytime Channel 4 show.

Some members of the crew are said to be unhappy that the 77-year-old presenter sleeps in her dressing room at Media City in Salford during breaks between episodes because it prolongs filming.

The row illustrates the enmity between supporters of Countdown co-presenter Rachel Riley and allies of Ms Robinson, with each camp coming up with unflattering nicknames for their rivals.

Ms Riley is said to be dubbed 'Princess Nut Nut' – the same demeaning name alleged to have been given to Boris Johnson's wife Carrie by Downing Street opponents – whole some crew members are understood to refer to Ms Robinson as the 'Wicked Witch'. 

However the famously acid-tongued and thick-skinned presenter may not be too perturbed by that moniker.

A source said that amid the feud 'there is another conundrum for the production team – Anne's nanna naps. She sleeps in breaks but then things end up getting delayed, which is irritating for staff who don't want to hang around all day.

'That said, she is a phenomenal woman, and it is, of course, no secret that she isn't getting any younger.'

The Mail on Sunday revealed last month that Ms Riley, 35, had become irritated by Ms Robinson's so-called 'grand ways'. 

It was later claimed that Ms Robinson had her co-presenter's microphone muted after complaining that Ms Riley's banter with contestants before filming began was 'too loud'.

While allies of each woman have briefed journalists off the record about a frosty atmosphere, Ms Robinson and Ms Riley have – at least in public – sought to downplay suggestions of a rift.

Ms Robinson, who has two grandchildren, recently said: 'Every time, I'm astonished how she [Rachel] does that adding up and subtracting – just seconds, absolutely seconds, amazing.'

In return, Ms Riley, who joined Countdown in 2012, said of the former Weakest Link host: 'Anne's not the cuddliest person in the world, but it's just a different show now, she's making it her own. She's getting some stuff out of the contestants – sometimes it's barbed, sometimes it's funny, it's just got a different flavour.'

Channel 4 declined to comment.