The ONS weekly deaths data shows an increase of 6,000 deaths over the five-year-average in week 14, and 8,000 in week 15, corresponding to 60% and 80% increases respectively. Most -- but, notably, not all -- of this increase is attributable to Covid-19. Most, too, of the excess deaths are occurring in people aged 50 and over (I haven't checked the statistical significance exactly but it's clear by eye).
There's therefore no doubt that Covid-19 is causing a rise in mortality rate. The question that can only be answered at the end of the year is whether the annual mortality rate is higher than the average, or whether the fact that most people dying of Covid-19 has co-morbidities that would have led them to die within a few months anyway.
In either case, the statistics are showing a clear and undeniable increase in mortality rate.