The BBC admitted it had a disappointing week but pointed to better ratings on Bank Holiday Monday and to original dramas such as the Legend of the Tamworth Two.
A BBC spokesman said: 'Last week was tough for us with 22 per cent, but it was a tough week for all terrestrial channels. There were a number of factors, including the fact that it was children's holidays and there were a number of big football matches.
'From our viewpoint, we have a schedule of breadth and depth with dramas such as England Expects, and a documentary from Panorama which was put in peak time.'
One BBC insider said executives would be most concerned by the fact that so many viewers were switching over to cable and satellite-channels which captured 26.1 per cent of all viewers.
The BBC's worst week comes at a time of turmoil - it doesn't have a director general, following the resignation of Greg Dyke in the wake of the damning Hutton report.
And populist Michael Grade does not take over as chairman until next month.
Although Mark Byford is standing in as acting director general, many at the BBC feel the corporation is rudderless.