OTTAWA – Statistics Canada is walking back a key census finding that stoked political fires in Quebec and saying that the English as a mother tongue is on the decline in the province instead of on the rise.

The change is the result of an error that the national statistics office says resulted in some 55,000 people recorded in last year’s census as English speakers who really had French as their mother tongue due to a computer error.

The result is that anglophones make up 7.5 per cent of Quebec’s population, rather than 8.1 per cent. Statistics Canada now says English as a mother tongue declined by two-tenths of a percentage point in the overall share of the population between 2011 and 2016, instead of an increase of four-tenths of a percentage point as first reported.

The embarrassing mistake for the agency also means that the proportion of Quebec’s population reporting French as their mother tongue has declined less than Statistics Canada originally believed.

The agency is also revising downward the country’s bilingualism rate to 17.9 per cent from 18 per cent, which the agency had touted as an all-time high for the country.

In Quebec, the jump in English-language speakers caused emotional ripples, with provincial politicians talking about legislative means to ensure the survival of the French language in the province.

The rise was most dramatic in some smaller cities and in the provincial capital of Quebec City. The mistake in Quebec City caused 5,700 people to be incorrectly counted as English speakers.

After days of questions about how such a rise could have occurred, given trend lines and other information like school enrolment figures pointed in the opposition direction, Statistics Canada took a second look at the numbers.

What officials found was that a mistake in the online prompts caused answers to be transposed when they were entered into the system. Officials narrowed down the mistake to 61,000 respondents who did a follow-up step when they failed to complete the questionnaire.

Census officials are standing by the new numbers that have been verified by an outside panel of experts and stress that the revisions do little to change the overarching story line about Canada’s linguistic makeup revealed earlier this month.

Statistics Canada officials are reviewing what went wrong and implementing new processes to prevent similar mistakes in future census releases.