Scripts had to be rewritten for the Ferreiras, Ms Berridge says

In the Mirror poll 16% of the 2,157 surveyed deemed the slump "dramatic".

Louise Berridge said that "success goes in cycles" and that stories about the show's troubles were more newsworthy than stories about its success.

But she conceded that some storylines with the show's Ferreira family were "not our finest hour".

The greater the success of the programme, the more news value there is to be had from any perception of its failure Louise Berridge Executive producer

The poll, conducted by YouGov, found that more than half - 53% - wanted to see better plots while 36% though the characters needed to improve.

Ms Berridge said: "The greater the success of the programme, the more news value there is to be had from any perception of its failure."

She said the most important rule of soap was to listen to feedback and that was why she was "taking the unusual step of responding" to the survey.

"It's disappointing to read that a large number of viewers feel the show has been weaker over this last year - although to some extent I fear this was inevitable.

"In a way, it's been a victim of its own success."

'Negative impact'

She said the popularity of storylines with Kat Slater and Alfie Moon, as well as scenes involving Dennis Rickman and Sharon Watts, meant that some viewers complained if their favourite characters were "not the centre of storyline".

She said matters "beyond our control", including pregnancy and illness, often had a "negative impact" on the show.

In the case of the Ferreira family, the "sudden removal" of actor Dalip Tahil meant a major storyline had to be scrapped and 40 scripts "rewritten on the spot".

Mr Tahil was deported to his home country of India following a decision by the Home Office to reject his appeal to work for the BBC in the UK.