Covid-19 pandemic, experts have warned.Leading charity Cancer Research UK said it is "really worried" about the impact of the crisis.It said there is a “danger of replacing one health crisis with another in time" if cancer services are not restored over the winter.They said it is “essential” these services recover from the toll of the pandemic.The warning came as the charity estimated that three million people in the UK have missed out on cancer screening since the end of March.And more than