This makes the BBC One programme the most watched science programme ever and the 19th most popular BBC show ever.

A total of 15m people watched or recorded the show on Monday 4 October and 3.91m watched the repeat on Sunday, according to BARB (Broadcasters' Audience Research Board).

These impressive figures make it the most watched programme of the week, beating every episode of EastEnders and Coronation Street.

Unlike its prehistoric subjects, the show is proving to be a lasting hit.

The third episode of the animated programme was watched by 12.5m people according to unofficial overnight figures, only slightly less than the unofficial overnight figures for the earlier programmes.

"It's a monster hit," said a spokeswoman from BBC Science, the department which spent three years and £6m making the series.

Record-breaker: Only Fools And Horses

But the all-time record for BBC viewing figures is still held by EastEnders. An audience of 30.1m watched Dirty Den Watts give Angie her divorce papers on Christmas Day 1986.

The final episode of Only Fools And Horses on 29 December, 1996 was the most watched single BBC programme with 24.35m viewers.

Skating duo Torvill and Dean's failed attempt at Olympic gold in February 1994 attracted an audience of 24m and 22.8m tuned in to see Princess Diana's Panorama interview in November 1995.