The response goes further than the statement issued by a spokesman yesterday which just apologised for the timing of the caption. The formal response admits the caption was wrong and promises it will not happen again.
The BBC statement says
The Over the Rainbow trail in Doctor Who should not have played out on Saturday and we apologise to all Doctor Who fans whose enjoyment of the show was disrupted. We recognise the strength of feeling that has been expressed and are taking steps to ensure that this mistake will not happen again.
It is understood that the instruction to run the caption was made by BBC One management and was made without consulting the programme's producers or senior management at BBC Wales.