Yes, it quite probably was... but some people are far too eager to extrapolate that it was widespread in January, when deaths only started rocketing from late March (see chart below).
fullfact.org/media/uploads/UK_spike_chart.png
The only possible ways this can be explained are:
a) Covid was either not present, or only present in very low numbers in January (which isn’t consistent with office blocks being struck down with it - but just working through it - as per other threads) , and any flu-like illnesses over that period were the flu - as happens every winter!
b) A precursor to the current Covid virus was present but somehow mutated in March to a much more dangerous illness... In which case the illness people had in January wasn’t really the same at all (in the same way I couldn’t really say I had “Spanish Flu” in 1917, a year before that pandemic).... but i’ve not seen a shred of evidence that this occurred.
c) the Government, along with all other world Governments, even those that are a loggerheads (USA, Iran, Russia, Germany etc.) have all colluded to falsify death statistics to artificially reduce them in January and increase them dramatically in March.
Of these, a) is overwhelmingly more likely to be the case